Allen-Bradley. User Manual. Stepper Positioning Assembly. (Cat. No QA)

Transcription

1 Allen-Bradley Stepper Positioning Assembly User Manual (at. No. 77 QA)

2 Important User Information Because of the variety of uses for the products described in this publication, those responsible for the application and use of this control equipment must satisfy themselves that all necessary steps have been taken to assure that each application and use meets all performance and safety requirements, including any applicable laws, regulations, codes and standards. The illustrations, charts, sample programs and layout examples shown in this guide are intended solely for example. Since there are many variables and requirements associated with any particular installation, Allen-Bradley does not assume responsibility or liability (to include intellectual property liability) for actual use based upon the examples shown in this publication. Allen-Bradley publication SGI., Safety Guidelines For The Application, Installation and Maintenance of Solid State ontrol (available from your local Allen-Bradley office) describes some important differences between solid-state equipment and electromechanical devices which should be taken into consideration when applying products such as those described in this publication. Reproduction of the contents of this copyrighted publication, in whole or in part, without written permission of Allen Bradley ompany, Inc. is prohibited. Throughout this manual we make notes to alert you to possible injury to people or damage to equipment under specific circumstances. ATTENTION: Identifies information about practices or circumstances that can lead to personal injury or death, property damage or economic loss. Attention helps you: Identify a hazard. Avoid the hazard. Recognize the consequences. Important: Identifies information that is especially important for successful application and understanding of the product. Important: We recommend you frequently backup your application programs on appropriate storage medium to avoid possible data loss.

3 Table of ontents Introduction Assembly and Installation Programming and Operation hapter Description Understand ompliance to European Union Directives EM Directive Low Voltage Directive hapter General Input onsiderations Power Supply onsiderations I/O Power Supply Auxiliary Power Supply Stepper Translator and Power Supply Stepper Motor Pulse Output Expander Module Module Disassembly Output Format (S) Input Logic (S) Expander Module Address (S3) Expander Module Output (S4, S, S6) Diagnostic Indicators Stepper ontroller Indicators Expander Module Indicators Installation System Grounding onsiderations able onsiderations Shield onnection Module Keying ompatibility Module Specifications hapter 3 General Positioning oncepts Move Definition Moveset Positioning Modes Single-Step Mode Jog ontinuous Mode Synchronization of Axes Publication 77-UMA EN P May

4 ii Table of ontents Independent Mode Data Block oncepts Moveset Block Moveset ontrol Word Offset Word Preset Word Initialization Preset Move Preset Move Block Single Move ontrol Word Move Data Time Final Decel Position Status Block Status Word Status Bits Position Words Block Transfer Programming Block Transfer Overview Bidirectional Block Transfer Data Address and Module Address Block Length Multiple Writes of Different Block Lengths to One Module File Addresses Enable and Done bits Example Instructions Programming onsiderations Programming Strategy Block Length Programming ommands Data Table Sizing onsiderations Data Table Documentation Forms Data Table Expansion Handshaking Block Transfer Timing PL-/3 (PL-/) Remote System PL-/3 Local System Mini-PL-/ ontroller Application onsiderations Move Duration Reversing Direction During a ontinuous Sequence Decel and Position onsiderations for a Hz Move Override Time onsiderations Stepper Motor Acceleration onsiderations Publication 77-UMA EN P May

5 Table of ontents iii Resonant Frequency Accuracy of and Decel Times Minimum Move Time Example Programs Troubleshooting Specifications SA Hazardous Location Approval hapter 4 General Axis Program Programming a -Axis Profile Preset and Jog Data Move Data Ladder Diagram -Axis Program Operational Summary Axis Program Programming a 3-Axis Profile Operational Summary hapter General Troubleshooting Tables Illegal Bit ombinations Appendix A Pulse Output Expander Module Specifications (cat. no. 77-OJ) A Stepper ontroller Module Specifications (cat. no. 77-M).... A Appendix B SA Hazardous Location Approval B Publication 77-UMA EN P May

6 iv Table of ontents Publication 77-UMA EN P May

7 hapter Description The Stepper Motor Positioning Assembly (cat. no. 77-QA) allows programmable control of stepper motors by Allen-Bradley programmable controllers. Data and commands set to the stepper positioning assembly are converted to a pulse output for a user-supplied stepper motor translator which in turn provides the proper voltage and current to the stepper motor to produce the desired motion. The stepper motor positioning assembly consists of: P Processor Bi Directional Block Transfer Stepper ontroller Module (cat. no. 77-M) Pulse Output Expander Module (cat. no. 77-OJ) Field Wiring Arm (cat. no. 77-WB) One stepper controller module can control up to three pulse output expander modules. The system can be expanded modularly from one to three axes per I/O chassis by placing from one to three output expander modules in the chassis (Figure.). The pulse output expander modules can be located in any slot except the left-most slot and in any order in the I/O chassis. 77 M Stepper ontroller Module Figure. Typical System Block Diagram 77 I/O Rack Backplane ommunications 77 OJ 77 OJ 77 OJ Pulse Pulse Pulse Output Output Output Expander Expander Expander #3 # # Move Data Axis # Status Data Axis # Axis # Translator Stepper Motor Axis # Move Data Axis # Axis #3 Translator Stepper Motor Axis # Move Data Axis #3 Translator Stepper Motor Axis #3 9 Publication 77-UMA EN P May

8 Introduction Stepper motor positioning assemblies can be used in applications requiring more than three axes by using additional I/O chassis. The stepper assemblies can be distributed throughout the plant using remote I/O or data highway configurations. Typically, each axis can control a linear slide although not limited to that type of mechanical load. The axes can be controlled independently or control of the axes can be synchronized. Programming is based on a data block format where blocks of data can be manipulated using block format instructions such as file-to-file move and block transfer read and write instructions. The stepper positioning assembly can be used with any Allen-Bradley programmable controller that has block transfer capability and an expandable data table except for Mini-PL- (cat. no. 77-LN3) and PL-/ (cat. no. 77-LP) Processors. When using the PL-/, programming will be more lengthy because data must be transferred using repeated get/put (word) transfer instructions. The number of axes that can be controlled and the complexity of motion will depend on the memory available for the positioning program after the data table of the P processor has been expanded to store the data blocks. Understand ompliance to European Union Directives If this product has the E mark it is approved for installation within the European Union and EEA regions. It has been designed and tested to meet the following directives. EM Directive This product is tested to meet ouncil Directive 89/336/EE Electromagnetic ompatibility (EM) and the following standards, in whole or in part, documented in a technical construction file: EN 8-EM Generic Emission Standard, Part Industrial Environment EN 8-EM Generic Immunity Standard, Part Industrial Environment This product is intended for use in an industrial environment. Low Voltage Directive This product is tested to meet ouncil Directive 73/3/EE Low Voltage, by applying the safety requirements of EN 63 Programmable ontrollers, Part Equipment Requirements and Tests. Publication 77-UMA EN P May

9 Introduction 3 For specific information required by EN 63-, see the appropriate sections in this publication, as well as Industrial Automation Wiring and Grounding Guidelines For Noise Immunity, Allen-Bradley publication Open style devices must be provided with environmental and safety protection by proper mounting in enclosures designed for specific application conditions. See NEMA Standards publication and IE publication 9, as applicable, for explanations of the degrees of protection provided by different types of enclosure. Publication 77-UMA EN P May

10 4 Introduction Publication 77-UMA EN P May

11 hapter General The stepper positioning assembly can be wired for -axis operation with a stepper translator and motor as shown in Figure.. One stepper controller module can control up to three pulse output expander modules installed in the same chassis. When the application calls for -or 3-axis control, each additional expander module should be wired as shown in Figure.. No more than one stepper controller module can operate in an I/O chassis. Figure. Typical -Axis onnection Diagram Pulse Output Expander Module Field Wiring Arm 77 WB Input Output NE lass NE lass Power Power + Supply + Supply Fwd Dir Rev Dir + D Input Supply + D Output Supply ommon Stop Input Jog Forward Input Jog Reverse Input Not Used Not Used Not Used Not Used Fwd Rev Pulses/ Directional Signals Stepper Translator and Power Supply Mechanical Load Stepper Motor Input onsiderations Pulse output expander modules can be controlled manually by the use of switch inputs for stop, jog forward and jog reverse. The stop switch will cause output pulses to the corresponding axis to cease instantaneously. Jog switches are operational only when the corresponding axis is at rest. Publication 77-UMA EN P May

12 Assembly and Installation Input switch contacts should be compatible with the voltage and current levels of the input circuits. The pulse output expander module will accept inputs from open collector logic devices or grounded switch contacts, and inputs from the Allen-Bradley Encoder/ounter Module (cat. no. 77-IJ, -IK). Refer to section titled Module Specifications for additional input specifications. Power Supply onsiderations Each module in the I/O chassis including the processor or adapter module draws power from the I/O (chassis) power supply. Some modules require an additional power source. I/O Power Supply Power is supplied through the I/O chassis backplane from the V D I/O power supply. The stepper controller draws all of its power (.7A, maximum) from the I/O power supply. Each pulse output expander module requires a current of.8a maximum. These amounts (4.A maximum for a 3-axis system) should be totalled with the current requirements of all other modules in the chassis so as not to exceed the maximum output current of the I/O chassis power supply. Auxiliary Power Supply Pulse output expander modules require an additional power source for switch inputs to the module and for pulse outputs to the stepper translator and motor. The power source can be separate input and output power supplies for one, two or three axes, a combined power source for each axis, or a combined power source for up to three axes. The power supply must be NE lass listed. Each input switch draws ma maximum when closed. The maximum output current for the pulse output expander module is ma. Refer to Appendix A, Module Specifications for additional information concerning the auxiliary power supply requirements. The supply voltage can be any value chosen from V D to 3V D required by the user-selected stepper translator and/or the switch input circuits. The variation in the D voltage level due to ripple should not exceed the input specification for the stepper translator because the supply voltage ripple appears at the output terminals of the pulse output expander module. Power supplies with mv peak-to-peak ripple can be used. However, check the translator input specification to ensure that the power supply specifications meet translator input requirements. The supply may require input filtering to guard against electrical noise. Publication 77-UMA EN P May

13 Assembly and Installation 3 Stepper Translator and Power Supply The stepper translator and power supply convert digital information from the pulse output expander module into the proper voltage and current for the precise control of a stepper motor. For compatibility with the pulse output expander module, the translator must accept low true logic. The programmed maximum pulse rate from the pulse output expander module to the translator can be any value up to, pulses per second. Stepper Motor The stepper motor converts electrical pulses into mechanical movements. The motor shaft rotates through a specific angular rotation for each pulse. The movement is repeated precisely with each pulse and the shaft rotates in fixed, repeatable increments. When a threaded shaft is used to drive a linear slide, the velocity, distance and direction of the slide can be precisely controlled. The stepper motor, stepper translator and translator power supply should be grounded to guard against electrical noise interference in accordance with the manufacturer s specifications and guidelines. Improper grounding can result in unwanted extra pulses occurring at the stepper translator and/or stepper motor. Pulse Output Expander Module Prior to installation, a pulse output expander module must be configured to correctly interface with the corresponding stepper translator. Adjustments are made using six switch assemblies. The functions of the switches are summarized in Table.A and described in subsequent paragraphs. Module Disassembly The switch assemblies are located on the module printed circuit board. They are accessed as follows:. Remove the four screws from the upper and lower edges of the labeled cover.. Remove the printed circuit board from the covers and set it solder-side down. 3. Locate the switch assemblies labeled S through S6 as shown in Figure.. Publication 77-UMA EN P May

14 4 Assembly and Installation Table.A Summary of Internal Switch Functions Switch Assembly Function Description Output Format Separate forward and reverse pulse outputs, or Pulse out, direction output Input Logic low = true or high = true 3 Expander Module Address Each expander module must have a different binary address, either,,or 3. 4,, 6 Module Output Push-Pull or urrent Source (open emitter), or urrent Sink (open collector). Figure. Location of Dip Switch Assemblies S S S3 ON S4 S S6 OFF OFF OFF ON ON Publication 77-UMA EN P May

15 Assembly and Installation 4. Set the switches as described in the following sections. Some switches are labeled on/off. Others may be labeled open for the off position.. Reassemble the module. Start all four screws before tightening to facilitate alignment of the covers and printed circuit board. Output Format (S) The output format that determines forward or reverse motion differs between translators. Therefore, the output terminals of the pulse expander module are user-selectable to match the required pulse input configuration of the translator. There are two basic translator input configurations. Some translators are designed to receive a pulse train at either one of two terminals, depending on the direction of rotation desired in the stepping motor. With this type of translator, a pulse train sent from the pulse output expander module to one of the translator terminals causes the stepping motor to rotate in the forward direction. An identical pulse train sent from the module to the other translator terminal causes the stepping motor to rotate in the reverse direction. Output terminals on the pulse output expander module can be selected in accordance with Table.B. Table.B Output Format (S) Switch Assembly S Switch Switch Output Terminal Active Output onfigurations & Logic Levels Logic Level When Stopped either ON or OFF OFF High Forward Pulse train Reverse Pulse train High High High OFF ON Pulse train Low (Forward) High High (Reverse) Low High Last State Last State ON ON Pulse train Low (Forward) High High (Reverse) Low High High High Note: Low = true logic Publication 77-UMA EN P May

16 6 Assembly and Installation Other translators are designed to receive only one pulse train at a single pulse terminal. These translators usually have a separate terminal for direction information. If a high (or low) signal is sent to the direction terminal, the stepping motor rotates in the reverse direction. If a low (or high) signal is sent to this terminal, the stepping motor rotates in the forward direction. The rate of rotation (in either direction) is controlled by the pulse train at the pulse terminal. The status of the pulse output expander module s outputs when motion has stopped is also user-selectable. The settings of switch assembly S for the output format are summarized in Table.B. Input Logic (S) The choice of low true or high true logic for manual control of the pulse output expander module s hardware inputs is user-selectable. The S switch assembly settings are summarized in Table.. Table. Input Logic (S) Switch Number Motion ontrol Input Logic STOP OFF = High true ON = Low true JOG FORWARD 3 JOG REVERSE OFF = High true ON = Low true OFF = High true ON = Low true Expander Module Address (S3) Each pulse output expander module must have its own (binary) address for communication with the stepper controller module. Allowable addresses are (), () or 3 (). They can be set using switches and. Switch 3 is always off. No other combinations of the S3 switch assembly settings are valid. Refer to Table.D. Publication 77-UMA EN P May

17 Assembly and Installation 7 Table.D Expander Module Address (S3) Switch Assembly S3 Expander Switch Switch Switch 3 Address ON OFF OFF OFF ON OFF ON ON OFF 3 Expander Module Output (S4, S, S6) The choice of pulse output expander module output, either push-pull, current source (open emitter) or current sink (open collector), is user-selectable to best match the input characteristics of the stepper translator. PUSH-PULL-OPEN The push-pull output is compatible with many stepper translators. The expander module output is wired to the translator input as shown in Figure.. URRENT SOURE or URRENT SINK-OPEN When using the expander module as a current source or sink for the output pulses, it may be necessary to use a pull-down or pull-up resistor, respectively (Figure.3) Refer to the translator input specifications and installation instructions for correct use of this resistor if it is required. Figure.3 Output Source or Sink onnections 3 Expander Module ommon Direction +Supply Pull Up Resistors (urrent Sink) or Pull Down Resistors (urrent Source) Supply Translator The positive (+) and negative (-) terminals of the output power supply must be connected to the + D OUTPUT SUPPLY and OMMON terminals, respectively, of the module field wiring arm regardless of the choice of module output. Publication 77-UMA EN P May

18 8 Assembly and Installation! ATTENTION: Avoid shorting any of the output terminals to ground, to the common terminal, or to the positive (+) terminal of a power supply. Damage to the module could occur. The settings of switch assemblies S4, S and S6 for the desired module output are summarized in Table.E. Set all switch positions in assemblies S4, S and S6 to the same output configuration. Table.E Expander Module Output (S4, S, S6) Switch Assembly Switch Switch Output Terminal Module Output S6 ON OFF ON OFF ON ON urrent Source (Open Emitter) urrent Sink (Open ollector) Push-Pull S ON OFF ON OFF ON ON urrent Source (Open Emitter) urrent Sink (Open ollector) Push-Pull S4 ON OFF ON OFF ON ON urrent Source (Open Emitter) urrent Sink (Open ollector) Push-Pull Set all switch positions in assemblies S6, S, and S4 to the same output configuration. Diagnostic Indicators The stepper controller and pulse output expander modules have LED indicators. Their color and function are described in the following paragraphs. Stepper ontroller Indicators Three LED indicators are located on the upper front panel of the stepper controller module. They perform the following functions. P OMMUNIATIONS FAULT (Red) This indicator is normally off. If a communications fault between the stepper controller module and the P processor is detected, or a stepper controller module hardware fault is detected, this indicator will illuminate. Publication 77-UMA EN P May

19 Assembly and Installation 9 EXPANDER OMMUNIATIONS FAULT (Red) This indicator is normally off. If a communications fault between the stepper controller module and any one of the pulse output expander modules is detected, or a hardware fault in any one of the pulse output expander modules is detected, this indicator will illuminate. Important: If both red indicators illuminate simultaneously at power-up, the stepper controller module has a hardware fault. ATIVE (Green) This indicator illuminates unless a hardware fault on the stepper controller module is detected causing it to turn off. At power-up this LED will not illuminate until the P processor is in run mode. This indicator will flash on/off if, after power-up, an invalid expander address is detected, no expander module is present and/or another stepper controller module is detected in the same I/O rack. Expander Module Indicators Five LED indicators are located on the upper front panel of the pulse output expander module (Figure.4). They perform the following functions: MODULE FAULT (Red) This LED is normally off. If an expander module hardware fault is detected, it will illuminate. OUTPUT PULSE RATE (Green) This LED is normally on or flashing at the output pulse rate whenever an output is present. STOP INPUT (Orange) This LED illuminates when a hardware stop input is asserted. JOG FORWARD (Orange) This LED illuminates when a hardware jog forward input is asserted. JOG REVERSE (Orange) This LED illuminates when a hardware jog reverse input is asserted. Installation The stepper positioning system is susceptible to electrical noise unless the equipment is properly grounded, the cabling is properly shielded and the power supply(ies) is properly filtered. If not, an incorrect number of position pulses could result. Publication 77-UMA EN P May

20 Assembly and Installation System Grounding onsiderations The following should be connected to earth ground: Ground prong of all A line cords Negative (-) or common terminal of the I/O power supply(ies) One I/O chassis mounting stud Ground the drain wire of the cable connecting the pulse output expander module to the stepper translator. This cable should be grounded either at the translator or at the I/O chassis, but not both. See Shield onnection below. The stepper translator, power supply and motor should be grounded in accordance with the manufacturer s instructions.! ATTENTION: Improper system grounding can result in additional unwanted pulses occurring at the stepper translator and/or stepper motor. Unpredictable machine motion could occur with possible damage to equipment and/or injury to personnel. able onsiderations The stepper translator should be wired to the field wiring arm using a twisted 3-conductor shielded cable (Belden 877). The cable distance between the pulse output expander module and the stepper translator generally should not exceed 4 feet. Shield onnection Belden 877 cable has a foil shield with a bare drain wire. The shield should be connected to earth ground at one end of the cable only. This can be at the customer end of the cable or at an I/O chassis mounting bolt or stud. At the other end of the cable, the shield should be cut short, bent back and taped to insulate it from any electrical contact. This practice helps to guard against unwanted radiated electrical noise and ground current loops. Module Keying Plastic keying bands shipped with each I/O chassis provide an easy method for keying an I/O slot to accept only one type of module. Use of the keying bands is strongly recommended. Publication 77-UMA EN P May

21 Assembly and Installation The module is slotted in two places on its rear edge. The position of the keying bands on the backplane connector must correspond to the slots to allow insertion of the module so that only the desired module will fit in this slot. Refer to Figure.4. Snap the keying bands on the upper backplane connectors between these numbers printed on the backplane: Stepper ontroller and 4 8 and Expander Module 8 and and 4 Needle-noise pliers can be used to insert or remove keying bands. Figure.4 Keying Diagram Stepper ontroller Expander Module(s) Keying Bands ompatibility An I/O chassis that contains a stepper controller module may not contain another master intelligent I/O module. Module Specifications The pulse output expander module specifications and stepper controller module specifications are listed in Appendix A. Publication 77-UMA EN P May

22 Assembly and Installation Publication 77-UMA EN P May

23 hapter 3 General The desired motion of the stepper motor can be accelerated, decelerated or maintained at constant rate by controlling the pulse rate from the pulse output expander module. Motion can be rotational such as used to position an indexing table, or can be linear such as obtained when a linear slide is driven forward or backward by turning a threaded shaft. In either case, the position at any given moment is defined by the number of pulses sent to the stepper motor. It can result in some number of degrees of rotation or linear units of travel. The motion can be programmed by manipulating data table words (control blocks) arranged in a convenient format. Blocks of data are also used to indicate that commands were received and desired motion was implemented (status block). ontrol and status blocks are communicated bidirectionally between the P processor and stepper controller module by block transfer programming. The task of programming requires that control and status block be assigned in the data table and that control data be entered using the industrial terminal. ontrol blocks sent to the stepper controller module by write block transfers govern acceleration, deceleration, final rate and final position. ontrol blocks also contain control words. Bits in control words must be set according to the particular application and desired motion. The stepper controller module sends status blocks of data to the P processor using read block transfers. Status blocks contain current position information and diagnostic bits set by the stepper positioning assembly. The format of the data blocks and the function of status and control bits will be covered later in this chapter. Positioning oncepts There are three stepper positioning concepts which should be understood before learning how the stepper positioning assembly is programmed. They are: Move Definition Moveset Positioning Modes Publication 77-UMA EN P May

24 3 Programming and Operation Move Definition A move in its simplest form consists of an acceleration of the stepper motor axis, a final rate, a deceleration to zero and a final position (Figure 3.). The value for an acceleration is the time required to achieve a final rate. Values can be chosen from seconds. The final rate determines the constant speed of machine motion. The final rate value can vary from to, pulses per second. The decel value, any value from seconds, is the time required to decelerate to zero pulses per second from a final rate. The final position of a move is the number of pulses between and 999,999 to be achieved by the move. The physical location will depend on the resolution (pulses per degree of rotation or pulses per inch of travel, etc.) of the stepper translator/motor configuration and the specific application (gearing threads per inch of the linear axis, etc.). Figure 3. Move Definition Final (, Pulse/Sec) (Accel) (-9.99 Sec) Decel (-9.99 Sec) Final Position 999,999 Pulses Position 4 Moveset A moveset refers to the data used to control from to moves. Sequential moves can be blended to form a continuous move profile or can be implemented one move at a time where motion stops between moves. A moveset can be executed using a minimum of ladder diagram programming. Two or more movesets can be implemented sequentially as if they were a single large moveset. The stepper positioning assembly can store two movesets simultaneously for up to three axes. When one moveset is in operation (working moveset), the next moveset is in storage (storage moveset). In the continuous mode, the last move of the working moveset is blended with the first move of the storage moveset. Publication 77-UMA EN P May

25 Programming and Operation 3 3 In any mode, when the working moveset is finished, the storage moveset automatically becomes the next working moveset. Then another (storage) moveset can be block transferred to the stepper positioning assembly. In the continuous and independent modes of operation, the storage moveset must be received by the stepper controller module before the third from last move of the working moveset is complete (for example, move 8 of moves). In the single-step mode, the storage moveset must be received before the second from last move of the working moveset is completed. Skipped moves (section titled Move Block, Bit ) are not counted. The use of multiple movesets allows long and complex positioning profiles or long sequences of single moves to be performed with little additional programming. The moveset is further defined in section titled Moveset Block. Positioning Modes The stepper positioning assembly can be programmed for operation that is tailored to the application requirements. The positioning modes determine the type of positioning profile and the manner in which the axes of two or three stepper motors can be coordinated. The stepper positioning assembly can also be operated manually using hardware or software jog inputs. Single-Step Mode In the single-step mode, a moveset allows the individual moves to be controlled one at a time. A start command from the P processor starts the first move of the sequence. After the move is completed, the stepper motor axis stops and a done bit is set. In order for the next move to begin, the P processor must transfer another start command to the stepper controller module (Figure 3.). Figure 3. Single Step Mode Final Final Decel Decel Move Move Move 3 Final Decel Time Start ommand Final Position Start ommand Final Position Start ommand Final Position Done Bit Done Bit Done Bit is set is set is set Note: Jogging between moves causes a system fault.. Publication 77-UMA EN P May

26 3 4 Programming and Operation Jog A jog allows an axis to be manually controlled by an operator independent of other axes in the system. This can be done at any time except when a positioning profile is in progress. A jog can be initiated by a hardware or software input to the stepper positioning assembly. Jog data is one move block that controls one axis. The job move block typically is contained in a separate -move (-word) moveset. The jog move block can also be contained in a moveset with other moves. If so, the jog must be the first move of the moveset. The remaining moves will be ignored as a result of the stepper controller module processing the jog move block. After the jog has been executed as needed, the remaining moves can be initiated by again transferring the same moveset to the stepper controller module. This time a skip bit must be set in the jog data and the jog load bit must be cleared. (These bits are described in section titled Move Block, Bit and 3). The positioning profile will then start with move two and ignore the jog data. The jog can be initiated by jog forward or jog reverse user-supplied input switches or by ladder diagram logic. An axis must be at rest before a jog can be initiated. As long as the jog input is asserted, the jog will continue at the specified rate. Once released (off) the jog will decelerate to a zero rate over the time defined by the decel value programmed in the jog move. If desired, the final position value can serve as an upper (or lower) limit of jog travel. The jog will automatically decelerate to reach a zero rate at the programmed final position if the jog input is held on. If the final position value of the jog is programmed as zero, the limit of travel will be 999,999 pulses. If the decel value is programmed as zero, the jog rate will cease instantly when the jog input is turned off.! ATTENTION: Avoid damage to the stepper motor and machine by selecting jog final rate and decel values which are compatible with the stepper motor/machine dynamics. Publication 77-UMA EN P May

27 Programming and Operation 3 ontinuous Mode The continuous mode allows moves of the moveset to be blended continuously into a move profile with fully programmed accelerations and decelerations. One start command is required for the entire positioning profile. A done bit is set at completion. Each move is defined as having a ramp, a final rate and a final position. The last move of the profile, in addition to the ramp, final rate and final position, contains a deceleration to zero (Figure 3.3). The decel value does not affect the positioning profile in any move except the last move. Figure 3.3 ontinuous Mode Final 3 Final 3 Final Start ommand Final Position Final Position Decel 3 Move Move Move 3 Done Bit is set Position Final Position 3 Synchronization of Axes All axes (up to three) can be synchronized move-by-move in the single-step and independent modes. Each axis must complete a given move before any axis is allowed to begin the next move. oordination is independent of P processor scan time. If two axes are synchronized, then the third axis, if used, must also be synchronized. Synchronized axes must operate in the same positioning mode. A start command can be programmed for only one of the synchronized axes. In the single-step positioning mode, this must be done for each move of the moveset. Start commands received during a move will be ignored. Done bits for all axes must be set before a start command is executed. In the continuous and independent modes, one start command is required at the beginning of the synchronized profiles. Publication 77-UMA EN P May

28 3 6 Programming and Operation A done bit is set for each axis at completion of each positioning profile. If all axes (up to three) are not synchronized, then the control of any axis is completely independent of the other(s). Three different single-axis machines could be controlled by one stepper controller module and three pulse output expander modules in one I/O chassis. Independent Mode The independent mode allows a chain of single-step moves to be sequentially executed. Each move is defined as having a ramp, final rate, decel (to Hz rate) and a final position. Typically there is a pause of -3ms from the end of one move to the beginning of the next (dwell at Hz rate). Refer to Figure 3.4. One start command is required for the entire positioning profile. A done bit is set at the completion of each move. Important: Done bits which are set between moves in the independent mode should not be used because they remain set for too short a time. Only the done bit of the last move should be examined. This can be achieved by examining the number that identifies the last move (status bit -3) and the done bit in the same rung. Figure 3.4 Independent Mode Final Decel Final Decel Final Move Move Move 3 Decel Position Start ommand Done Bit is set The done bit remains set until the start of the next move (msec dwell time, nominal) 7 Publication 77-UMA EN P May

29 Programming and Operation 3 7 When using the independent mode and the axes are synchronized, all but the last axis to finish the move in process will stop motion when finished and wait for the last axis to complete its move. All axes will then begin the next move simultaneously as soon as the last axis has finished its move. The process then repeats for each move in the positioning profile (Figure 3.). Figure 3. Synchronized Axes (Independent Mode) Expander # Done Bit is set Move Move Time Expander # Done Bit is set Move Move Time Expander # 3 Done Bit is set Move Move Time Start ommand Done bit remains set until start of next move. Done bit dwell time, msec, nominal. 8 Publication 77-UMA EN P May

30 3 8 Programming and Operation Data Block oncepts Words that control the motion of the stepper motor axis, record position or monitor move diagnostics are stored in data table files. These words are grouped into the following three kinds of data blocks. Moveset Block Move Block Status Block In addition to move data, the blocks contain special control or status words. The bits in these words affect how the motion is controlled or verify that the move commands and the move data were received and implemented. Moveset Block The moveset block is a data table file for storing data and controlling the motion of one stepper motor axis. It allows move data to be stored in consecutive data table words to control up to moves of a positioning profile. Each axis must have at least one moveset block. A moveset block must contain the following move data (Figure 3.6). Moveset ontrol Word Offset and Preset Words One or more Moves Figure 3.6 Moveset Block and Positioning Profile 64 Word Moveset Block in Data Table Moveset ontrol Word Offset word MS Preset Word LS Preset Word The 64-word moveset block may contain from to move blocks. If using less than move blocks, fill all unused words with zeros or a programming error results. Move Block # Move Block # Move # Interim Moves Move # Position Move Block # 3 Move Block # 9 Move Block # 9 Publication 77-UMA EN P May

31 Programming and Operation 3 9 Moveset ontrol Word A moveset block must contain a moveset control word as the first word in the block. Each of the bits of the moveset control word serves a function in the control of a stepper motor axis. Bit functions of the moveset control word are defined below and summarized in Figure 3.7. Figure 3.7 Moveset ontrol Word MW Override Moveset Jog Forward Jog Reverse Offset Not Used (Must be zero) Axis Address Axis Address Start Profile Mode Select Profile Mode Select Synchronized Axes Reset Global/Axis Stop Decel/Instantaneous Axis Addr. Bit Bit 3 Mode ontinuous Independent Single Step Bit N/A Bit Bit Start ommand Bit. When this bit is set, the stepper controller module will start to execute the first move of a continuous or independent mode sequence or the next single step move. Bit, Mode Select Bits. These two bits are used to determine the type of positioning profile. Bit =, Bit =: ontinuous Mode (Figure 3.3) Bit =, Bit =: Independent Mode (Figure 3.4) Bit =, Bit = or : Single-Step Mode (Figure 3.) Refer to section titled Positioning Modes for mode descriptions. Publication 77-UMA EN P May

32 3 Programming and Operation Bit 3 Synchronized Axes Bit. If this bit is set for any axis, it must be set for the other axes so that all (two or three) axes controlled by the stepper positioning assembly are synchronized. Synchronized axes must be operating in the same positioning mode. (Bits,, and 3 must be set identically in the moveset control words of the synchronized axes.) Refer to Synchronization of Axes. Bit 4 Reset ommand Bit. A reset command can be limited to a single axis or can reset all axes (up to three) depending on the logic state of the global/axis bit (bit ). With the exception of the done bit and reset bit, all status and position information and all moveset data are cleared in the stepper controller module when the reset command bit is set. The reset bit and done bit are reset in the status word at the start of the first move in the next moveset. The user program should clear the reset bit after the reset has been executed as indicated by reset bit in the status word. Refer to section titled Status Block. Bit Global/Axis Bit (for stop or reset commands, only). When this bit is set, all axes controlled by the stepper positioning assembly are stopped or reset with one command. (The notation refers to a low logic state.) When this bit is zero, only the axis of the moveset defined by the axis address bits (bits and ) is stopped or reset. The function of this bit should be considered whenever the stop bit (bit 6) or the reset bit (bit 4) is programmed. Bit 6 Stop ommand Bit. When this bit is set, output pulses will cease either in a controlled decel or instantly, depending on how the decel/instantaneous bit (bit 7) is set. A stop command can be limited to a single axis or can apply to all axes (up to three) depending on how the global/axis (bit ) is set. All move profile data is cleared, but position and status information remains the same in the stepper controller module when this bit is set. The user program should clear the stop bit after the stop command has been executed as indicated by reset bit in the status word. Refer to section titled Status Block. Bit 7 Decel/Instantaneous Bit. When this bit is set, the output pulse rate will decelerate to zero in accordance with the decel value in the move block that was being executed when a software stop command was received. Publication 77-UMA EN P May

33 Programming and Operation 3 When the decel/instantaneous bit is zero, output pulses will cease instantly when a software stop command is received. A hardware stop input in instantaneous, independent of the decal/instantaneous bit. This bit is generally set when a stop bit is set. Bits, Axis Address Bits. These bits define the axis to be controlled by the data and/or commands in the moveset block. The address in the moveset control word of the moveset block must be identical to the settings of the address switch assembly (S3) of the corresponding pulse output expander module. The address bits of the moveset block are generally set when the profile is initially programmed using the industrial terminal. The setting of bits and respectively are = axis, = axis, = axis 3. Bit Must always be zero. Bit 3 Offset ommand Bit. When set, the value contained in the offset word (described below) will be added to or subtracted from the final position value(s) of all moves of the moveset blocks residing in the stepper controller module memory. In all modes, the final position of each move is shifted by the offset amount and direction. Bit 7 of the offset word determines the direction of the shift, for subtracted or for added. Important: The present move being executed and the move following may not be affected by the offset command in all but the single step mode. In the single step mode, only the present move will not be affected. The user program should clear the offset bit and allow the stepper controller module to see the bit cleared before another offset for that axis is enabled. Bit 4 Software Jog Reverse ommand Bit. The axis will move in the direction indicated for as long as this bit is set or until the final position programmed in the jog move is reached. Hardware jog inputs are disabled during this time. The jog will follow the ramp, rate, decel and final position values programmed in the jog move block. In large systems or systems using remote I/O, the software jog timing will depend on block transfer timing. Refer to section titled Handshaking. Publication 77-UMA EN P May

34 3 Programming and Operation The load jog command bit (bit 3 of the single move control word, defined in section titled Move Block ) must be set to identify jog move block data. The user program should clear the software jog reverse command bit and allow the stepper controller module time to see the bit cleared before another jog to that axis is enabled. Bit Software Jog Forward ommand Bit. Same as bit 4. See software jog reverse command bit. Bit 6 Moveset Bit. Successive movesets can be programmed for continuous execution using the moveset bit. This bit can be used to label each block transfer of move data as moveset or moveset. When movesets are alternately labeled for the first, for the second, for the third, etc., user program logic can sequence the movesets without interruption as if they were one large moveset. The number of successive movesets is limited only by processor memory. Once a positioning profile has begun, none of the moves of the working moveset can be updated. However, the storage moveset in the stepper controller module can be updated provided that the moveset bit in the transferred (updated) moveset has the same setting ( or ) as the storage moveset bit. Refer to section titled Movesets. In large systems or systems using remote I/O, moveset timing will depend upon block transfer timing. Refer to Handshaking, page 3 3, for more information. Bit 7 Override ommand Bit. The override bit is set in the moveset containing the override data. When the override command is enabled, the override bit causes the current moveset to be interrupted and the override moveset to be blended immediately. The first move of the override moveset is blended with the interrupted move in progress. Refer to section titled Override Time onsiderations to ensure that the first move of the override moveset will be compatible with any worst case move in progress. Generally, bits of the moveset control word are set by user program logic. A command to the stepper controller module should be cleared and the stepper controller module allowed sufficient time to see the bit cleared before the next command is transferred. See the section titled Handshaking. Publication 77-UMA EN P May

35 Programming and Operation 3 3 Avoid sending multiple commands to the stepper controller module at the same time. A programming error could result or the data/command could be ignored. All bits must be set carefully to tailor the move profile(s) to the application requirements and to avoid illegal bit combinations. If only one command is transferred at a time with proper handshaking, no difficulty should be encountered. An illegal bit combination will cause a programming error when data is received by the stepper controller module or when move data is processed for execution. Once the definitions of the bit functions have been learned, the table of illegal bit combinations found in section titled Illegal Bit ombinations, can be consulted as an aid in avoiding programming errors when programming the required move profile(s). Offset Word The position offset allows an entire positioning profile (all moves of the profile) to be shifted to compensate for machine wear without reprogramming the profile (Figure 3.8). The offset value between and 7,999 pulses, can be added to or subtracted from the final position of each move in the moveset(s). Figure 3.8 Offset Offset Move Move Move 3 Position The offset value is entered in BD in bits -6 of the offset word. Bit 7 is the control bit that determines whether the offset will be added to or subtracted from the final position (Figure 3.9). The value entered in the figure is the maximum allowable value of offset. Refer to offset command bit 3 of the moveset control word described earlier in this section Publication 77-UMA EN P May

36 3 4 Programming and Operation Figure 3.9 Offset and Preset Words Data Table 7 7 MW = Add = Subtract Offset = Assert Initialization Preset MS Preset = Move Preset LS Preset The moves affected by the offset will be those stored in the working and storage moveset when the command is received. If additional movesets have been programmed, the offset command must be re-enabled when additional movesets are transferred to the stepper controller module. Preset Word The preset word can store values that serve two functions. One function, initialization preset, is used by the stepper controller module to define the starting point value of the positioning profile. The other function, move preset, can be used to extend one or more moves of the profile beyond the 999,999 pulse (position) limit of the stepper controller module. In either case, the preset word can be loaded with the necessary value, the function enabled and another value loaded as needed. When used, the preset value becomes the new position reference of the profile. The preset can be any value between and 999,999. Preset data is contained in two words, one for the most significant (MS) 3 digits, the other for the least significant (LS) 3 digits (Figure 3.9). Preset values are entered in BD in bits -3. Bits 4-7 in the LS preset word and bits 4-6 in the MS preset word are undefined and must be loaded with zeros. Bit 7 of the MS preset word is the assert bit for the initialization preset. Publication 77-UMA EN P May

37 Programming and Operation 3 Initialization Preset Typically it may be necessary to jog the machine to a starting position before the positioning profile(s) is (are) started. The position register of the stepper controller module will read some number of position pulses representing the machine starting position. The initialization preset can be used to reset the value of the position register to zero, or to any value that would be used as the profile starting value. If the preset value were not set equal to zero (or not equal to the profile starting value), when started, the first move(s) of the profile would be shortened or lengthened. The amount would be the difference between the initialization preset and the starting point value: shortened if the preset exceeded the starting point value or lengthened if the value were less than the starting point value (Figure 3.).! ATTENTION: All moves must achieve a final rate for a minimum duration of ms or a programming error and a system fault will result. The minimum duration of a move is covered in section titled Application onsiderations. Figure 3. Initialization Preset and Starting Value Preset > Starting Value Preset = Starting Value Preset < Starting Value Position Move Initialization Preset Final rate must be mainained for ms, minimum 3 Bit 7 of the MS preset word is the assert bit for the initialization preset. When this bit is set, the preset value will be written over whatever value is in the position register of the stepper controller module. Once the positioning profile has been started, bit 7 must not be set or a programming error will occur. Publication 77-UMA EN P May

38 3 6 Programming and Operation Move Preset The move preset can be used to adjust the starting point value of any move in a moveset whenever necessary. For example, the move preset can extend one or more moves of the profile beyond the 999,999 pulse limit of the stepper controller module. The move preset is enabled by bit in the single move control word (see section titled Move Block ). When this bit is set, the position register of the stepper controller module and the starting point value of the move block will become the value stored in the preset words. The final position value of the move block and all subsequent move blocks will be referenced to this new starting point value. If a move profile extends beyond 999,999 pulses and the application calls for a return to the home position, it may be necessary to change the preset value and again set the move preset bit (Figure 3.). When necessary, this must be done before the move to home position is started. Reverse travel to the home position can require two moves if the total travel exceeds 999,999 pulses. Figure 3. Move Preset Move Preset, Forward 999k Position Reverse Move Preset 999,999 (to return) 4 Publication 77-UMA EN P May

39 Programming and Operation 3 7 Move Block A move block contains ramp, final rate, final position and deceleration data that characterize a move. A moveset block must contain from to move blocks. A move block contains the following words (Figure 3.): Single Move ontrol Word Move Data Figure 3. Single Move ontrol Word Always to identify the Always Zero Move Preset Multiplier Move Skip Load Jog 6 Single Move ontrol Word The single move control word is the first word in each move block. The word contains two identification bits (bits 6, 7) and four bits which affect the operation of the move (bits -3). The function of each bit is defined below and summarized in Figure 3.. Bit Move Preset Bit. This bit, when set, causes the value contained in the preset words of the moveset block to become the starting point value for that move. The position register becomes this value. The preset value can be changed and re-enabled as needed to further extend the position limit or to allow the profile to return to the home position. Refer to Move Preset. Bit Multiplier Bit. When the rate multiplier bit is set, final rates can be selected in pulses per second increments between and, pulses per second. When this bit is zero, any final rate from to 9,999 pulses per second can be selected in pulse per second increments. This bit would typically be set when ramp, rate and decel values are initially set in the data table using the data monitor mode of the industrial terminal. Publication 77-UMA EN P May

40 3 8 Programming and Operation Bit Skip Bit. The skip bit allows one or more moves of a moveset to be ignored without reprogramming. When this bit is set, the corresponding move block is skipped over. When operating in the continuous mode, the move preceding the skipped move and the move following the skipped move are blended automatically. Refer to section titled Application onsiderations to ensure that the blend is achievable without a programming error. When operating in the independent mode, the move following the skipped move begins as soon as the one preceding the skipped move is done. Skip bits can be set initially in the data table when move data is entered or they can be set by user program logic. Skip bits must be set before the moveset is transferred to the stepper controller module. Once the moveset is transferred, additional skip bits cannot be set in that moveset. Bit 3 Load Jog Bit. This bit is set to identify the accompanying move block as jog data. Bit 4 software jog reverse command or bit software jog forward of the moveset control word can be programmed to initiate the jog. Jog data (with the load jog bit set) can be transferred to the stepper controller module with the software jog forward or reverse command (bit or 4), or jog data can be transferred to the stepper controller module in advance. See software jog forward and reverse command bits and 4 of the moveset control word described earlier in this section. Refer to the section titled Jog. An axis reset command will clear any previously transferred jog data for that axis. Bit 4- Must always be zero. Bit 6, 7 Identification Bits. Both bits must be set to identify each single move control word. Otherwise, a programming error will occur. Generally, bits of the single move control word are set by user program logic. A command to the stepper controller module should be cleared and the stepper controller module allowed sufficient time to see the bit cleared before the next command is transferred. See Handshaking. Avoid sending multiple commands to the stepper controller module at the same time. A programming error could result or the data/command could be ignored. Publication 77-UMA EN P May

41 Programming and Operation 3 9 Move Data Move data is contained in the remaining five words of the move block (Figure 3.3). Values are entered in BD. Those shown in Figure 3.3 are the maximum allowable values. Undefined bits (bits 4-7) in the words specifying the ramp, decel and position must be filled with zeros. Figure 3.3 Move Block Data Table 7 7 Single Move ontrol Word Seconds ,999 x, x Pulses per second Decel seconds ition ition ,999 Pulses Time The ramp value is the number of seconds the positioning assembly will take to reach a (new) final rate. In the continuous mode, the final rate can be greater than or less than the starting rate. time can be any value between and 9.99 seconds. Refer to section titled Application onsiderations. Final The final rate value determines the constant speed of the move. The rate can be any value between and 9,999 pulses per second or in increments of pulses per second between and, pulses per second. Refer to section titled Application onsiderations. Important: When the rate multiplier bit (bit ) of the single move control word is set, the resulting rate will be equal to the programmed rate value times ten. Decel The deceleration value is the number of seconds the positioning assembly will take to decelerate to zero pulses per second. It should not be confused with a ramp to a lower final rate other than zero. The decel is an active part of the move profile in the single step and independent modes. Publication 77-UMA EN P May

42 3 Programming and Operation In the continuous mode, the decel value is not used in the move profile except for the last move. However, the decel value has a special purpose in the continuous mode: it allows a controlled decel to Hz rate under two conditions:. If a system fault is detected, the move in progress will decel to a Hz rate (come to a stop) in the time defined by the decel value.. If a software stop command is received by the stepper controller module, a controlled decel to a Hz rate will occur during the move in progress. This will happen only if the decel/instantaneous bit of the moveset control word is set. Otherwise the stop will be instantaneous.! ATTENTION: Select a decel value for a controlled stop that is compatible with the stepper motor and system dynamics in order to avoid damage to the equipment. Refer to section titled Application onsiderations. Position The position value defines the final position of any particular move. It is the number of position pulses from a reference value such as the beginning of the move profile. When the number of pulses defined in the position words of a move block equals the number of pulses sent from the pulse output expander module to the stepper translator, that particular move is done. The most significant digits of the position value are contained in the MS position word, the least significant digits in the LS position word. Use leading zeros when necessary. Status Block The status block is a data table file used to store position and diagnostic information received from the stepper controller module. The status block contains the following word storage for each pulse output expander module (axis). Status Word Position Word Publication 77-UMA EN P May

43 Programming and Operation 3 The first word in the status block is reserved for future use (Figure 3.4). Each expander module then uses three words, the first of which is the status word. The remaining two are position words. The number of status and position words returned to the P processor depends on the highest numbered axis in the stepper positioning assembly, not on the number of axes used. The status block must contain four words if only axis is in the system, seven words if axis is the highest numbered axis, and ten words if axis 3 is in the system. Figure 3.4 Status Block Data Table 7 7 Reserved For Future Use Status Word, Axis Pulse Output Expander Module # * ition ition Status Word, Axis Pulse Output Expander Module # * ition ition Status Word, Axis 3 Pulse Output Expander Module #3 * ition ition * reports a negative position 7 Publication 77-UMA EN P May

44 3 Programming and Operation Figure 3. Status Word Status word Done Moveset Jog Forward Jog Reverse Move Number (-A Hex) ommand Verified Data Received Direction Rev/Fwd System Fault Programming Error Reset Program Stop Hardware Stop Status Word The bits in the status word allow the P program to verify that move commands have been received and implemented. The bits can be monitored visually or used to display which portion of the positioning profile is currently in operation, the status of the current move and the nature of any fault or error detected by the stepper controller module. The functions of the status word bits are defined below and summarized in Figure 3.. Status Bits Except as noted below, the status bits verify that a particular command has been received by the stepper controller module. Bit ommand Verify Bit. This bit is set to verify that a command bit (start, stop, offset, jog reverse, jog forward, override, initialization preset or load jog) has been received. Bit Data Received Bit. This bit toggles alternately to or every time a new write block transfer is received. Bit Direction Bit. This bit indicates the direction of rotation, for forward or for reverse. Publication 77-UMA EN P May

45 Programming and Operation 3 3 Bit 3 System Fault Bit. This bit is set if a system failure such as a communication error is detected in the stepper positioning assembly, or invalid data is detected. The output decelerates to Hz at the programmed decel value when a system failure is detected. Bit 4 Programming Error Bit. This bit will be set for a number of error conditions including the following. Illegal bit combinations exist in the data transferred to the stepper controller module. Refer to Table., Illegal Bit ombinations, in hapter. The identification bits (bits 6 and 7) of the are not set. Any undefined bit is set (other than zero) in the following words: MS Preset (bits 4-6) LS Preset (bits 4-7) (bits 4-7) Decel (bits 4-7) ition (bits 4-7) ition (bits 4-7) values exceed, pulses per second. or decel values exceed 9.99 seconds. Preset or position values exceed 999,999 pulses. Important: The stepper controller module checks these conditions when data is first received. At a later time when a move is being processed for execution, other invalid data can be detected. Invalid data (such as that which would cause the final rate of a move to be held for less than ms) will cause both a programming error (bit 4) and a system fault (bit 3). The positioning profile would then cease. Bit Reset Bit. This bit is set when a reset command is received and at power-up. Anytime a reset command is received, the done bit and reset bit will be on. Both bits are reset when the first move of the next moveset begins. Bit 6 Software Stop Bit. This bit is set when a software stop command is received. Bit 7 Hardware Stop Bit. This bit is set when a hardware stop (E-STOP) command is received. Publication 77-UMA EN P May

46 3 4 Programming and Operation Bits -3 Move in Progress Bits. The bit pattern in Hex shows which move (-) of the moveset is currently being executed. (decimal =Hex A). Bit 4 Jog Reverse Bit. This bit is set when a software jog reverse command has been received or when a hardware jog reverse input is asserted. Bit Jog Forward Bit. This bit is set when a software jog forward command has been received or when a hardware jog forward input is asserted. Important: If the jog final position value is reached (upper or lower limit) during a software jog, the status bit 4 or will be reset even if the software jog command remains asserted. However if a hardware jog is being executed, the status bit 4 or will remain set until the hardware jog input is removed. Bit 6 Moveset Bit. This bit indicates the number ( or ) of the current moveset being executed. The moveset bit will alternately toggle to or when multiple movesets are executed. Bit 7 Done Bit. This bit will be set after every move in the single-step mode or independent mode; or after a move profile is completed in the continuous mode. It is reset when the first move of the next moveset begins. Refer to independent mode in section Positioning Modes concerning the use of this bit in the independent mode. Position Words Position words report the number of pulses that have been sent to the stepper translator (provided that the position register in the stepper controller module has not been changed by a preset). The P processor can then continually monitor the number of output pulses which in turn indicates the present position of the machine. Two position words are required to store the number of position pulses, one to store the three most significant digits and the other to store the three least significant digits. The position pulses which can range from to 999,999 are stored in BD in the lower bits of each word (Figure 3.4). Publication 77-UMA EN P May

47 Programming and Operation 3 The values shown in the figure are the maximum allowable values for position pulses. Bits 4,, 6 of the MS position word and the upper four bits of the LS position word are undefined. They will be read block transferred to the P processor as zeros. Bit 7 of the MS position word is used to indicate a negative position. For example, a reverse jog to below zero will set bit 7. Bit 7 is zero for a position between and 999,999 pulses. Block Transfer Programming All communications between the stepper controller module and the P processor data table are controlled by program logic using block transfer programming. The Mini-PL-/ and PL-/3 programmable controllers use block transfer instructions. The PL-/ uses multiple get instructions for programming block transfer. Refer to the July 98 or later edition of the Programming and Operations Manual for the Mini-PL-/ or PL-/3 or the PL-3 Programming Manual for a detailed description of block transfer. These are publications 77-84, and 77-8, respectively. The remainder of this section describes block transfer concepts applicable to the stepper controller assembly using block instructions with the Mini-PL-/ or PL-/3 programmable controller. Block Transfer Overview The stepper controller is a bidirectional block transfer module. Bidirectional Block Transfer Bidirectional block transfer is the performance of alternating read and write operations. A read operation transfers data from the stepper controller module to the P processor data table. A write operation transfers data from the data table to the stepper controller module. Two rungs of user program are required, one containing the block transfer read instruction, the other containing the block transfer write instruction. The format of the block instructions and the definitions of terms are shown in Figure 3.6. Data Address and Module Address The data address is the block transfer instruction address. It is used to store the I/O rack address of the stepper controller module (module address). The module address is stored in BD by rack, module group, and slot number and identifies the module s location in the I/O rack. Publication 77-UMA EN P May

48 3 6 Programming and Operation The data address of a block transfer instruction should be the first available address in the timer/counter accumulated area of the data table. This address is 3 8 for the Mini-PL-/ controller. For the PL-/3 controller, this address depends on the number of I/O racks connected to the processor module, i.e. address 8 for one I/O rack, 3 8 for two racks, etc. to 7 8 for six racks and 8 for seven racks. When more than one block transfer module is used, the data addresses should be consecutive. Figure 3.6 Block Transfer Instruction Format BLOK XFER READ DATA ADDR MODULE ADDR 3 EN 7 BLOK LENGTH FILE DN 7 BLOK XFER WRITE DATA ADDR MODULE ADDR 3 EN 6 BLOK LENGTH FILE DN 6 Numbers shown are default values. Numbers in shaded areas must be replacced by uer-entered values. The number of default address digits initially displayed, 3, 4, or will depend on the size of the data table. Initially displayed default values are governed by the I/O rack configuration. Data Address: Module address: Block Length: File: Enable Bit ( EN ) : Done Bit ( DN ) : First possible address in accumulated value area of data table. Rack module group and slot number. Number of words to be transferred ( can be entered for default value or for 64 words.) Address of first word of file. Storage locations 8 above the data address. Automatically entered from the module address. Set to when rung containing the instruction is true. Automatically entered from the module address. Remains set to one scan following successful transfer. 4 Publication 77-UMA EN P May

49 Programming and Operation 3 7 Two consecutive data addresses must be used in bidirectional block transfer. Both contain the I/O rack address of the stepper controller module. For bidirectional operation, each data address word also contains an enable bit; bit 6 for a write operation and bit 7 for a read operation. When the P processor searches the data addresses in the timer/counter accumulated area of the data table, it finds two consecutive data addresses both containing the same module address. The read bit is set in one data address. The write bit is set in the other. When the P processor finds a match of the module address and enable bit (read or write bit) for the desired direction of transfer, it then locates the file address to which (or from which) the data will be transferred. The file address is stored in a word 8 above the corresponding data address. A boundary word containing zeros should be entered in the data table following the last block transfer data address. When the processor sees this boundary word, it will terminate the block transfer search routine so subsequent data table values cannot be interpreted as rack, module group and slot numbers associated with block transfer data addresses. Block Length The block length is the number of words transferred to or from the stepper controller module. The module can receive up to 64 words of a moveset block from the P processor in one write block transfer. It can transfer to the P processor up to words of status in one read block transfer. These are the maximum (default) block length values of the module. Only selected values as determined by the size of the moveset block or status block, not exceeding the default value, can be entered as the block length. The value of must be used to set the block length for a read or write block transfer to the default value (64 for a write operation or for a read operation). Multiple Writes of Different Block Lengths to One Module When two or more write block transfer instructions have a common module address, careful programming is required to compensate for the following possible situations: During any program scan, the enable bit can be set or reset alternately according to the true or false condition of the rungs containing these instructions. The true or false status of the last rung will govern whether the transfer will occur. Publication 77-UMA EN P May

50 3 8 Programming and Operation Secondly, the block length can be changed alternately in accordance with the block lengths of the enabled instructions. The block length of the last enabled write block transfer instruction having a common module address will govern the number of words transferred. File Addresses Two files are required for bidirectional block transfer: one to receive data transferred from the module, the other temporarily holding data to be sent to the module. The addresses of these files (in BD) are located in two consecutive storage locations in the preset area of the data table 8 above the corresponding consecutive data addresses in the accumulated area. The files themselves can be located elsewhere in the data table. Enable and Done bits The read enable bit is bit 7 or 7 of the module s output image table byte depending on whether the block transfer module is in a lower or upper slot, respectively. The write enable bit is bit 6 or 6 of this byte. In a bidirectional block transfer where the block lengths are unequal, one operation must not be enabled until the other is completed as determined by the done bit. The exception is when the block length is set to the default value for both the read and write operation. Then the P processor will automatically inhibit the alternate operation until the first is completed. The done bit has the identical bit number as the enable bit but the done bit is set in the module s input image table word. The done bit is set in the I/O scan that the transfer is made, provided that the transfer was successfully completed. The done bit remains set for one program scan. Example Instructions Example bidirectional block transfer instructions and their associated data table map are shown in Figure 3.7. The block lengths are set to the default value. Publication 77-UMA EN P May

51 Programming and Operation 3 9 Figure 3.7 Example Bidirectional Block Transfer Data Table R W Block length code ~ ~ R W Output image table low byte Data Addresses store the module address, rack, module group 3, slot. ~ R W ~ 3 Input image table low byte ~ Block Transfer Read File Words, Max. Addresses Available for Storage Block Transfer Write File 64 Words, Max. ~ Storage locations of file addresses Up to words of data are read from the module and located into the data table starting at word 8 when default block length is programmed. Up to 64 words of data are written to the bi-directional block transfer module starting from word 3 8 when default block length is programmed. BLOK TRANSFER READ DATA ADDR: 4 MODULE ADDR: 3 BLOK LENGTH: FILE: 77 BLOK TRANSFER WRITE DATA ADDR: 4 MODULE ADDR: 3 BLOK LENGTH: FILE: EN 7 3 DN 7 3 EN 6 3 DN 6 9 Publication 77-UMA EN P May

52 3 3 Programming and Operation Programming onsiderations This section describes how block transfer concepts can be applied to programming the stepper positioning assembly. It is assumed that an Industrial Terminal (cat. no. 77-T3) will be used and that the programmable controller is either an Allen-Bradley Mini-PL-/ or PL-/3. Programming Strategy Move commands and moveset blocks containing data of different block lengths can be transferred to the stepper controller module by programming one unconditional write block transfer instruction with a write block transfer file. Data blocks can be moved alternately into the write block transfer file and immediately transferred to the stepper controller module during the next block transfer. File-to-file-move instructions are used to transfer data blocks from their storage locations in the data table to the write block transfer file. When a transfer is needed, program logic enables the file-to-file move instruction. The block transfer is automatic because it is unconditionally programmed. Status data from the stepper controller module is transferred using one unconditional read block transfer instruction. The data is transferred into a buffer file where it is held temporarily until the P processor can verify that the transfer and the data are valid. Valid data can be moved to a final storage file where it can be manipulated by program logic. Invalid data is not moved from the buffer file but over-written by the next block transfer read operation. Examination of the read block transfer done bit is the condition for moving valid data into its final storage file. Following a transfer, the stepper controller module will set itself for the alternate read or write operation when the block lengths are set to the default value. Block Length The block length of read or write block transfer instructions must be set to default value,, causing the default mode of the stepper controller module to automatically perform block transfer handshaking. The stepper controller module will toggle from a write operation to a read operation and vice-versa. Important: Do not confuse block transfer handshaking (which verifies a successful transfer of data) with other recommended handshaking that examines the status bits in the axis status word. Status bits verify that a command and/or data have been received by the stepper controller module and indicate when the command can be disabled. Publication 77-UMA EN P May

53 Programming and Operation 3 3 When the block length of the read block transfer instruction is set to the default value,, the stepper controller module will automatically establish the default number of status words to be transferred; either four, seven or ten words. This number is determined by the highest address of a pulse output expander module contained in the chassis. For example, if the highest expander address were,, or 3, then the read block transfer would be four words, seven words or ten words, respectively. The remaining words of the 64 word default read block not used by the module can be used for timer/counter accumulated values and/or bit/word storage. Refer to Figure 3.7. When the block length of the write block transfer instruction is set to the default value,, the stepper controller module will expect to receive 64 words. The write block transfer file should also be 64 words long. During a write block transfer operation, 64 words will be transferred. However, all 64 words need not contain data. When transferring a moveset of less than 64 words, the unused balance of the moveset or write block transfer file must be cleared or voided. This can be done by loading zeros into all unused words or by programming the skip bit in the single move control word of each move to be skipped. The write block transfer file will contain data from the previous transfer. If the next moveset to be transferred contains fewer words of data than the previous transfer, the balance of the file will not be over-written but will accompany the new data. The stepper controller module, unable to distinguish between new and previous data, will operate on the entire transfer.! WARNING: To avoid unpredictable machine operation with possible damage to equipment and/or injury to personnel, be sure that the unwanted balance of transferred data is properly voided. This can be done using only one of the following methods: A. Loading zeros into all words remaining unused in the 64 word moveset file. In this case, zeros can be loaded into the moveset files initially when move data is programmed. For example, if only the first seven moves of a moveset are to be used, the last three moves (6 words) can be loaded with zeros. The zeros will over-write any data that could remain in the write block transfer file from the transfer of a previous moveset. Publication 77-UMA EN P May

54 3 3 Programming and Operation B. Setting the skip bit in the single move control words corresponding to unwanted move blocks. Program logic can be used to set bit in the 9th, 3rd, 47th word, etc. of the write block transfer file so that respectively the last, next to last, third from last, etc. move blocks of a moveset are skipped by the stepper controller module.. Programming the block transfers of multiple movesets so that each moveset is the same size or larger than the previous one. It will be necessary to clear the write block transfer file after the last moveset has been transferred in order to start the sequence again. Programming ommands When a command is transferred to the stepper controller module, the transfer will contain either one word or four words of new data. This will depend on whether the moveset control word (MW) alone, or the moveset control word, offset, and preset words are moved into the write block transfer file just prior to the transfer. Moveset data that remained in the write block transfer file from a previous transfer will accompany the command data. This unwanted moveset data may or may not have to be voided depending upon which command bit is set. Start MW, bit Usually accompanied by the first moveset after a reset or stop command, or after a profile has ended. The first moveset could have been previously transferred without the start command. If so, the stepper controller would process the data accompanying the command, load it into the working or storage area (writing over any previously loaded data) and execute the start of the moveset. Reset and Stop MW, bits 4 and 6 The stepper controller module clears all moveset data in both the working and storage areas and ignores all accompanying data when it receives a reset or stop command. Offset MW, bit 3 A block of four words is required to transfer an offset command with data (preset words must be included even if unused). The moveset data (unwanted) accompanying the offset command will be processed by the stepper controller module. hoose one of the methods for voiding unwanted data described in Block Length, above. Publication 77-UMA EN P May

55 Programming and Operation 3 33 Jog reverse and Jog forward MW, bits 4 and When either software jog command bit 4 or is enabled in the user program, the jog move will be executed if jog data had been previously transferred. The software jog command can be transferred to the stepper controller module with jog moveset data ( move) or can be transferred by transferring only a moveset control word with bit 4 or set. When the software jog command is transferred in the moveset control word alone, jog data (identified by load jog bit 3 set for an axis) must already be stored in the stepper controller module. The stepper controller module ignores all but the first words of jog moveset data if the load jog command bit is set. If this bit is not set, only the first four words of the moveset will be processed. Override MW, bit 7 An override moveset block of one to ten moves is required to transfer an override command. When the override command and data are received by the stepper controller module, the storage data in the module will be cleared and the override data will become the new working moveset. Refer to section titled Moveset Block, Override bit 7. Any moveset data (unwanted) accompanying the offset command will be processed by the stepper controller module. hoose one of the methods for voiding unwanted data described in Block Length, above. Initialization Preset MS Preset, bit 7 All moveset data is ignored by the stepper controller module when it receives an initialization preset command unless the load jog bit is set in the first move block. The initialization preset cannot be transferred after the move profile has begun. Load jog, bit 3 Must be set to identify the moveset block as data. See Jog reverse and Jog forward above. Data Table Sizing onsiderations The data table files that are used to store and transfer data to and from the stepper controller module should be considered with respect to available data table space. Typically, the data table will contain the following files: or more moveset files per axis- four overhead words plus six words per move, 64 words maximum. jog file per axis - ten words to store jog data. Publication 77-UMA EN P May

56 3 34 Programming and Operation write block transfer file - 64 words for the temporary storage of data to be write block transferred. read block transfer (buffer) file - When the block transfer read instruction is set to default,, this file uses four words for axis, seven words for axis or ten words for axis 3. The balance of this file can store other data because the balance is not used by the read block transfer instruction. status file - four words for axis, seven words for axis or ten words for axis 3, for storing validated status data. The minimum and maximum number of words typically required for the files are summarized in Table 3.A. Table 3.A Size of Data Files Data Table File Number of Data Table Words Move Axis Move Axis Move 3 Axis status file 4 4 temporary status buffer 4 [] 4 write block transfer file [] jog file 3 x moveset file Total x 64 [] 36 [] When programming only one move for axis, block length default values need not be used. Set the block length to the maximum number of words transferred. [] If multiple movesets are programmed, add 64 words maximum per axis per additional moveset. Data Table Documentation Forms Data table forms are available for recording the assignment of files (publication 44) and for recording move data contained in the files (Moveset Data form). These forms can be found at the end of this manual and should be reproduced as needed. Data Table Expansion The Mini-PL-/ and PL-/3 data tables are factory configured to 8 words. The number of 8-word data table sections can be increased to store the positioning profile data. This can be done using the data table configuration function. Press [SEARH][][] on the industrial terminal keyboard when the P processor is in program mode. Enter the required number of 8-word sections. The [ANEL OMMAND] key terminates this function. Publication 77-UMA EN P May

57 Programming and Operation 3 3 Important: Increasing the size of the data table by 8-word sections reduces the amount of words for user program by the same amount. Handshaking Handshaking is the exchange of commands and/or data with status information between the P processor and stepper controller module. Handshaking is normally used to ensure successful block transfers independent of data transfer times. The stepper positioning assembly uses any one of three handshaking cycles depending on the content and purpose of the transfer. The steps of the handshaking cycles are summarized below. YLE Transferring a command bit (start, jog forward, jog reverse, override, initialization preset, load jog) with or without accompanying data.. Enable the transfer containing the command bit (with or without accompanying data).. Observe that the command verify bit is set in the status word by the stepper controller module. 3. lear the command bit. 4. Observe that the command verify bit is then cleared in the status word by the stepper controller module. YLE Transferring a reset or stop command.. Transfer the reset or stop command.. Observe that the reset or stop bit is set in the status word. 3. lear the command bit. The reset or stop status bit will not be cleared until the first move of the next moveset begins. YLE 3 Transferring data with no command bit.. Observe whether the data receive (toggle) bit in the status word is set or reset.. Enable the transfer of data. 3. Observe that the data receive toggle bit changes to the opposite state. ommand bits are contained in the moveset control word, MS preset word and single move control word. Status bits are contained in the status word. ommand bits which directly correspond to bits in the status word during the handshaking cycle are presented in Table 3.B. Publication 77-UMA EN P May

58 3 36 Programming and Operation The command verify (status) bit will be reset whenever: A. the stepper controller module receives a transfer where none of the following command bits are set: start (bit ), stop (bit 6), offset (bit 3), jog (bit 4 or ), override (bit 7), initialization preset (MS preset, bit 7), and load jog (, Bit 3), or B. a reset command (bit 4) is received. The reset and stop bits will not be set in the status word until the pulse output expander module has actually performed the reset or stop command. Once set, the reset and stop (status) bits remain set until another move begins. The data receive bit (bit ) in the status word will toggle whenever the stepper controller module receives any new block transfer data and/or command. A command bit can be transferred to the stepper controller module by setting a command bit in the moveset control word and block transferring the moveset control word to the module. The moveset control word can be transferred alone (-word transfer), with the offset and preset words (4-word transfer) or with a moveset block where the transfer can vary in length by 6-word increments from words to 64 words. The moveset control word must always have its axis address bit(s) set. This is the only way that the stepper controller module can identify for which axis the transfer is intended. Move data cannot be transferred to the stepper controller module unless accompanied by the moveset control word, offset and preset words. Publication 77-UMA EN P May

59 Programming and Operation 3 37 Table 3.B orresponding Handshake Bits Moveset ontrol Word Moveset ontrol Word ommand Bit Function Bit Start ommand verify Reset 4 Reset Stop 6 Programmed Stop and ommand Verify 6 Offset 3 ommand Verify Software jog reverse 4 Jog reverse and ommand verify 4 Software jog forward Jog forward and ommand verify Override 7 ommand verify MS Preset Word ommand Bit Initialization preset 7 ommand verify Single Move ontrol Word ommand Bit Load jog 3 ommand verify Once set, the reset and stop status bits remain set until another move begins. Block Transfer Timing The time required for a block transfer read or write operation for PL- Family processors depends on the system scan time(s), the number of words to be transferred, the I/O configuration and the number of enabled block transfer instructions in the ladder diagram program during any program scan. A block transfer module will not accept another transfer until finished processing the previous transfer. For a worst case calculation of the time between block transfers, assume that the number of enabled block transfer instructions during any program scan is equal to the number of block transfer modules in the system. Also assume that the stepper controller module is operating in default mode so that 64 words or words are transferred in the write or read operation, respectively. The stepper controller module will toggle, when done, from one operation to the other in the next program scan. Publication 77-UMA EN P May

60 3 38 Programming and Operation The method for calculating the worst case time between block transfers will be covered for the following cases: PL-/3 remote and local systems, and Mini-PL-/ controller. PL-/3 (PL-/) Remote System The system scan time for a remote PL-/3 or PL-/ system is the sum of the processor scan time, the processor I/O scan time (between processor and remote distribution panel), and the remote distribution panel I/O scan time. Assume that for a remote system, the remote distribution panel can process only one block transfer operation per remote distribution panel scan. The procedure for calculating the worst case time between transfers under normal operating conditions can be done in four steps.. Write down the known facts.. alculate the system values that are determined by the system configuration. Program Scan PS = (ms/k words) x (number of program words) Processor I/O Scan PIO = (.ms/rack number) x (declared rack numbers) Remote Distribution I/O Scan RIO = (7ms/chassis) x (number of chassis) Number of Words Transferred W = default values of the module 3. alculate the block transfer time TW for the write operation and TR for a read operation. TW = PS + PIO + RIO +.W + 3 TR = PS + PIO + RIO +.W + 4 These equations are valid for up to, cable feet between the remote distribution panel and remote chassis and for a baud rate of 7.6k, or, cable feet at k baud rate. 4. alculate the worst case system time ST between transfers. ST = sum of transfer times of all block transfer modules in a system taken worst case (read or write). Publication 77-UMA EN P May

61 Programming and Operation 3 39 Example Problem A PL-/3 programmable controller is controlling 4 I/O racks in remote configuration (Figure 3.8). A 3-axis stepper positioning assembly is located in each rack. Assume that the stepper controller module is operating in default mode and that the ladder diagram program contains 4K words (K 4). There are no other block transfer modules in the system. Figure 3.8 Remote System Example 77 SD PL /3, System 77 QA 77 QA 77 QA 77 QA 77 AS 77 AS 77 AS 77 AS Rack No. Rack No. Rack No. 3 Rack No. 4 3 What is the worst case time between two consecutive write block transfers for this system when a 64 word moveset block is transferred to the stepper positioning assemblies and a ten word status block is returned to the P processor? Solution. Write down the known facts. Program length = 4K words Number of chassis = 4 rack numbers Number of default block transfer words = 64 words (write), words (read). alculate the system values. Publication 77-UMA EN P May

62 3 4 Programming and Operation Processor Scan Time PS = (ms/lk words x (4K words) = ms Processor I/O Scan Time PIO = (. ms/rack number) x (4 rack numbers) = ms Remote Distribution I/O Scan Time RIO = (7 ms/chassis) x (4 chassis) = 8ms Number of Words Transferred = 64 (write) or (read) 3. alculate the block transfer times, TW for a write and TR for a read operation. TW = PS + PIO + (RIO) +.W + 3 TW = + + (8) +.(64) +3 TW = 3ms (write) TR = PS + PIO + (RIO) +.W + 4 TR = + + (8) +.() + 4 TR = 87ms (read) 4. alculate the worst case system time ST between consecutive write block transfers. ST = 4TW + 4TR = 4(3) + 4(87) = = 84ms This is the worst case time between two consecutive write block transfers in the 4-chassis remote configuration described in example problem (enabled stepper assembly in each chassis). PL-/3 Local System The system scan time for a local PL-/3 system is the program scan time plus the processor I/O scan time Each block transfer module will be updated during a program scan. The procedure for calculating the worst case time between transfer can be done in four steps.. Write down the known facts.. alculate the system values that are determined by the system configuration. Program Scan PS = (ms/lk words) x (number of program words) Processor I/O Scan PIO (.ms/rack number) x (number of declared rack numbers) Number of words transferred W default values of the module Publication 77-UMA EN P May

63 Programming and Operation alculate the block transfer time T for the read and write operation. T =.ms + (.7ms/word x number of words transferred) The same equation is used for either read or write transfer times. 4. alculate the worst case system time ST between transfers. ST = PS + PIO + T() + T() + T(3) +... Example Problem A PL-/3 programmable controller is controlling four I/O racks in a local configuration (Figure 3.9). Otherwise this example problem is identical to example problem. Figure 3.9 Local System Example PL /3 77 QA 77 QA 77 QA 77 QA 77 AL 77 AL 77 AL 77 AL Rack No. Rack No. Rack No. 3 Rack No Solution. Write down the known facts. Program length = 4K words Number of chassis = 4 rack numbers Number of default block transfer words = 64 words (write), words (read). alculate the system values. Publication 77-UMA EN P May

64 3 4 Programming and Operation Processor Scan Time PS = (ms/lk words) x (4K words) = ms. Processor I/O Scan Time PIO = (.ms/rack number x (4 rack numbers) = ms Number of Words Transferred = 64 (write) or (read) 3. alculate the block transfer times T for the write and read operation. T =. + (.7ms/word x 64 words) = = 4.9ms (write) T =. + (.7ms/word x words) =. +.7 =.8ms (read) 4. alculate the worst case system time ST between consecutive write block transfers. The stepper controller module toggles to a read operation in the scan following completion of the write operation. ST = PS + PIO + T() + T() + T(3) + T(4) (writes) PS + PIO + T() + T() + T(3) + T(4) (reads) ST = PS + PIO + 4T (write) + 4T (read) = () + () + 4(4.9) + 4(.8) = = 67 ms This is the worst case time between two consecutive write block transfers in the 4-chassis local configuration described in example problem (enabled stepper assembly in each chassis). Mini-PL-/ ontroller The program scan and I/O scan are consecutive and are considered as a single processor scan. The Mini-PL-/ scan time varies typically from 8 to 4ms for a K program and one I/O rack. Each block transfer module will be updated during a program scan. The procedure for calculating the worst case time between transfers can be done in three steps.. Write down the known facts and system values. Processor Scan time PS = 4ms Number of Words Transferred W default value of the module. alculate the block transfer time T for the read and write operation. Publication 77-UMA EN P May

65 Programming and Operation 3 43 T =.ms + (.6ms/word x number of words transferred) The same equation is used for either read or write transfer times. 3. alculate the worst case system time ST between transfers. ST = PS + T() + T() + T(3) +... Example Problem 3 A Mini-PL-/ programmable controller is controlling one 3-axis stepper controller assembly in its I/O rack. The ladder diagram program contains K words. Otherwise, this example problem is identical to example problem. Solution. Write down the known facts and system values. Program length = K words Processor Scan Time PS = (4ms/lK words) x (K words) = 48ms Number of words transferred W = 64 (write, (read). alculate the block transfer time T for the write and read operation. T =.ms + (.6 ms/word x 64 words) (write) =. +.4 =.34ms (write) T =.ms + (.6ms/word X words) (read) =. +.6 =.7ms (read) 3. alculate the worst case system time ST between two consecutive write block transfers. ST = PS + T (write) + PS + T (read) = = 8 ms This is the worst case time between two consecutive write block transfers for the Mini-PL-/ controller as described in example problem 3. Publication 77-UMA EN P May

66 3 44 Programming and Operation Application onsiderations The values which can be selected for ramp and decel times, the final rate, and final position allow a very wide variety of move profiles to be programmed. However there are some constraints which, if not taken into consideration, can result in a programming error when the move profile is executed. These constraints, for the most part, should be considered when programming long acceleration times with brief but relatively high final rates. Selected values can be tested on paper using one or more of the following algebraic equations as appropriate. This can be done by substituting the selected values into the equation, performing the required mathematical manipulations and seeing whether the constraints are satisfied. Values can also be tested by running the program with the stepper translator disconnected. If the constraint(s) are not met as indicated by a programming error, then new values can be selected and tested until allowable values are found. Move Duration A move must remain at the programmed final rate for at least ms in order to avoid a programming error. This constraint must be satisfied for all moves but could likely be exceeded in moves covering short distances at high final rates. This constraint can be met in either of two ways: Decide where the final position must be. Then select and/or adjust the programmed ramp time, decel time (if part of the move) and/or final rate values accordingly. Select appropriate programmed ramp time, decel time (if part of the move) and/or final rate values and accept the resulting final position. The following equation can be used to test this constraint. Equation. RT (FR + IR) where: + FR DT +. < DELPOS RT = ramp time FR = final rate IR = initial rate DT = decel time (in the continuous mode, this term is zero for all but the last move) DELPOS = Difference in ELapsed POSition, the difference in number of pulses between the starting position and programmed final position of the move Publication 77-UMA EN P May

67 Programming and Operation 3 4 The following three examples show how this equation can be used. Example Problem : Single-step mode or independent mode. For the next move of a move profile, the change in move position from beginning to end (DELPOS) must be 6k pulses. Determine the maximum allowable final rate (FR) when using equal ramp and decel times of 4 seconds. The parameters of the equation (IR, FR, RT and DELPOS) and a sketch of the move are shown in Figure 3.. Figure 3. Single Step or Independent Mode ms FR IR RT DT Position DEL POS Start Position Final Position 3 Solution Write down the known facts.. RT = DT = 4 seconds DELPOS = 6k pulses IR = (The initial rate of a move in the single step or independent mode is zero by definition.) Find FR, the maximum final rate. 4(FR + ) 4 + FR +. < 6k hoose a value for FR, say k pulses per second. Publication 77-UMA EN P May

68 3 46 Programming and Operation 4(k + ) 4 + k +. < 6k k +.k <6k 4.k <6k This exceeds the constraint. The selected value of k was too large. Try FR = 6k. 4(6k + ) 4 + 6k +. < 6k K +.K <6k 4.k <6k This is within the constraint. The final rate of 6k pulses per second is allowable and can be used. Any value greater than approximately 6.4k pulses would cause a programming error when the move is executed. Example Problem : ontinuous Mode (except the last move) Determine the minimum final position (shortest allowable travel) of a move when the final position and final rate of the previous move were k pulses and k pulses per second, respectively, and the ramp time and final rate of the current move are RT = 3 seconds and FR = k pulses per second. The parameters of the equation (IR, FR, RT and DELPOS) and a sketch of the move are in Figure 3.. Figure 3. ontinuous Mode (Except the Last Move) ms FR IR RT Position DEL POS Start Position Final Position 3 Solution: Write down the know facts. Publication 77-UMA EN P May

69 Programming and Operation 3 47 RT = 3 seconds FR = k pulses per second IR = k pulses per second (final rate of previous move) DT = (decel time is zero in all moves except the last in the continuous mode, by definition) Find DELPOS, then add this figure to the final position of the previous move (K) to determine the minimum final position that can be programmed for the move. 3(k + k) + k +. < 6k 8k +.K <DELPOS 8.k <DELPOS The move final position value must be at least 8.k pulses beyond the previous move in order to ensure that the final rate will be maintained for ms. Therefore the minimum allowable programmed final position for the move is 8, pulses, obtained from adding the calculated value (8.k) to the final position of the previous move (k). Example Problem 3: Last Move in a ontinuous Mode The last move of a continuous profile must stop at a final position of 74k pulses. Determine if a selected decel time of seconds is acceptable if the final rate and final position of the previous move were k pulses per second and 68k pulses, respectively, and the ramp time and final rate (before decel) of the current move are RT = 6 seconds and FR = 6k pulses per second, respectively. Publication 77-UMA EN P May

70 3 48 Programming and Operation The parameters of the equation (IR, FR, RT and DELPOS) and a sketch of the move are shown in Figure 3.. Figure 3. Last Move in a ontinuous Mode IR FR ms RT DT Position DEL POS Start Final Position Position 3 Solution: Write down the known facts. RT = 6 seconds IR = k pulses per second (final rate of previous move) FR = 6k pulses per second DELPOS = 6k pulses (74k pulses - 68k pulses) 6(6k + k) DT + 6k +. < 6k DT 4k + 6k +. < 6k DT 6k +. < 8k DT +. <.33 DT <.3 Therefore, a decel time of seconds is acceptable for the move. Reversing Direction During a ontinuous Sequence In order to reverse direction during a positioning sequence in the continuous mode, a move to Hz rate must be achieved. The procedure for achieving a Hz rate as stated in the paragraph titled Decel and Position onsiderations for a Hz Move should be followed. Publication 77-UMA EN P May

71 Programming and Operation 3 49 Decel and Position onsiderations for a Hz Move A Hz rate move must be used when the profile is brought to a stop such as when reversing direction. When programming a Hz rate move, the ramp time and decel time are not used by the stepper controller module regardless of whether or not they are programmed. Only the rate (Hz) and final position values are entered. Either one of the following equations can be used to verify that a move to Hz rate allows ms of final rate before the decel begins. This constraint should be considered when any move in the continuous mode except the last move is brought to a Hz rate. If the actual executed decel time T is more important than the final position, then equation a should be used to calculate the correct DELPOS from which the correct programmed final position value can be obtained. DELPOS Programmed final position - starting position. The symbols means absolute value; disregard the sign in the answer. If a required final position of the move to Hz rate is more important than the actual executed decel time, equation b should be used to verify that the decel time T does not exceed 9.99 seconds. Equation a: Final Position Value T +.4 DELPOS = IR and Final Position Value = DELPOS + Final Position of the Previous Move. Equation b: Actual Decel Time T where: DELPOS IR.4 DELPOS = The difference in number of pulses between the starting position of the move and the programmed final position of the move. T = The actual time of the decel in seconds as executed by the positioning system (programmed ramp and decel times of the move are ignored). IR = Initial rate in pulses per second (final rate of the previous move). Publication 77-UMA EN P May

72 3 Programming and Operation The parameters of the equation (DELPOS, T and IR) and a sketch of the move are shown in Figure 3.3. Figure 3.3 Hz Move ms IR T Position DEL POS Start Position Final Position 33 Example Problem : The seventh move of a profile in continuous mode must be brought to Hz rate so that the profile can return to its starting point value. The final rate and final position of the previous move are 6k pulses per second and k pulses, respectively. The seventh move must reach a Hz rate at 6k pulses. What decel time should be programmed? How can this move be achieved? Solution: Write down the known facts. IR = 6k (final rate of previous move) DELPOS = k (6k - k pulses) T DELPOS IR.4 (Line ) T (k) IR.4 (Line ) T k IR.4 (Line 3) T = 3.7 seconds Publication 77-UMA EN P May

73 Programming and Operation 3 This exceeds 9.99 seconds. Either the position of the Hz rate move must be decreased, or the final rate of the previous move must be raised, or the final position of the previous move must be extended (or a combination of all three) in order to bring the decel time to 9.99 seconds or less. Assume that the DELPOS can be changed. If the DELPOS is reduced from k to 8k pulses, the actual decel time will be -.4 = 9.96 seconds (from line ) and within limits. In order to reduce the DELPOS to 8k pulses, the final position of the previous move would have to be extended by 3k pulses to 4k pulses. Override Time onsiderations During execution of an override move, the actual override ramp time executed by the stepper positioning assembly will vary depending on the rate which is being overridden. The override move must be programmed to guarantee that both the actual executed override ramp time and the programmed ramp time be in the range of seconds. The actual override ramp time is defined as the time required to change from the rate-in-process when the override command was received by the stepper controller module to the programmed override rate. The actual override ramp time as executed by the positioning system can be calculated using equation 3a. Equation 3b can be used to verify that a desired actual ramp time (ORT Act ) is possible by ensuring that the programmed ramp time (ORT Prog ) lies between and 9.99 seconds. These equations should be used with the maximum and minimum rates which could be overridden to ensure that the actual override ramp time is between and 9.99 seconds. The following equations can be used with any (IR) rate to be overridden. Equation 3a: Actual Override Time ORT Act ORT Prog x OFR IR OFR Equation 3b: Programmed Override Time ORT Prog ORT Act x OFR IR OFT where: ORT Act Act = Actual override ramp time ORT Prog = Programmed override ramp time OFR = Override final rate IR = Initial rate (rate in process when override occurs) OFR - IR = absolute value (if the difference is a negative number, consider it positive.) Publication 77-UMA EN P May

74 3 Programming and Operation If ORT Prog in equation 3a is zero, then ORT Act will be instantaneous (<ms). The equation parameters (ORT Act, ORT Prog, OFR, and IR) and a sketch of the move are shown in Figure 3.4. Example Problem : An override ramp time is programmed for 6. seconds. What will be the actual override ramp time if the override is enabled while a rate (IR) of 8k pulses per second is being executed? The final rate of the override move is k. Solution: Write down the known facts. IR = 8k pulses per second OFR = k pulses per second ORT Act = 6. seconds ORT Act ORT Prog x OFR IR OFR ORT Act 6. x k 8k 6.x k K k ORT Act.4seconds This is the range of seconds and is therefore acceptable. If the initial rate had been greater than k, then the absolute value of OFR-IR (negative difference considered as if positive) would have been used. Publication 77-UMA EN P May

75 Programming and Operation 3 3 Figure 3.4 Override Time OFR ORT Prog ORT Act IR Executed Profile Not Executed Override Move Position Move in Progress A) Override Time, OFR > IR IR ORT Act Must Not Exceed 9.99 Seconds Slope of executed override ramp will be equal but opposite to that of programmed override ramp. OFR Programmed Override ORT Prog Not Executed Executed Profile Position Move In Progress Override Move B) Override Time, OFR < IR 37 Publication 77-UMA EN P May

76 3 4 Programming and Operation Stepper Motor Acceleration onsiderations The stepper motor specifications will contain an acceleration limitation. It will state some maximum acceptable acceleration under load (change in pulse rate for a given duration, i.e. Hz/second). This motor acceleration constraint must be satisfied and should be considered especially when programming rapid accelerations to high final rates. The following equation can be used for a move that ramps from a Hz rate to a final rate. HZ > Final rate second motor RAMP time motor For example, a typical acceleration limit for a stepper motor could be, pulses per second per second for a given load. Programming a ramp time of second for a change in final rate from to, pulses per second would be pushing the motor to its maximum limit of acceleration since the slope of the ramp is k Hz per second. This is the fastest acceleration allowed for the motor. The same applies if ramping from one final rate to another such as when an override is blended with a move in process. In this case, the change in final rates must be considered. HZ > hange in Final rate second motor RAMP time motor In summary, if a programmed ramp is too quick for the motor/machine dynamics for accelerations and decelerations, the motor will not be able to keep up with the pulses being sent to it. If this occurs, some pulses may not be executed by the stepper motor and the indicated position value will be inaccurate. The status that is block transferred to the P processor would not longer state the actual position of the motor axis. Important: The position values represent the number of pulses sent to the stepper translator whether or not they are executed by the stepper motor. Resonant Frequency The stepper motor and load can have a resonant frequency within the operating range of to, pulses per second. When operated at or near the resonant frequency in a steady state condition or when accelerating or decelerating through this frequency, an increase in noise and/or vibration can occur. In extreme cases it is possible for the motor to oscillate and lose pulses. The resonant frequency can vary widely depending on the characteristics of the stepper motor and load. Publication 77-UMA EN P May

77 Programming and Operation 3 If the resonant frequency is encountered, its effect can be dampened or eliminated as follows: If encountered in a steady state condition (at or near a chosen final rate), increase the inertial load or change the final rate. If encountered when accelerating or decelerating through the resonant frequency, increase the rate of acceleration or deceleration by programming shorter ramp or decel times. In general, a stepper motor with no load is more apt to resonate than one that has a load. Accuracy of and Decel Times Output accuracy (variation) varies from less than +.% at k Hz to less than +.% at k Hz or lower (Table 3.). Table 3. Output Accuracy Programmed Output Accuracy khz-8.khz <+.% 8kHz-.kHz <+.% khz-hz <+.% The accuracy of the executed ramp or decel time will depend on the programmed ramp or decel time, and the rate to which the ramp is programmed or from which the decel is programmed. The maximum variation in executed ramp and decel times is shown in Table 3.D. Table 3.D and Decel Time Accuracy Programmed Pulse, to Hz +%, to Hz +% to Hz +% to Hz +% Variation in /Decel Time achieved by a ramp, or the rate from which a decel begins. In addition, ms could be added or subtracted to the value of the ramp or decel times between and second. Publication 77-UMA EN P May

78 3 6 Programming and Operation Minimum Move Time A minimum move in progress time is required by the stepper controller module to process the next move of a sequence, and to evaluate and act on incoming commands. Every move sent from the stepper controller module to a pulse output expander module must have a duration long enough to allow the stepper controller module to service the remaining expander modules, process any new commands and return to the original expander module before the move has ended. This minimum move duration must be long enough to allow any programmed combination of events in any mode of operation. If not, a programming error and system fault will result. However, if jog or move data, offsets or overrides are not transferred to the stepper controller while a profile is being executed, then the shortest executable move time can be used as stated in Table 3.E. Table 3.E Minimum Move Time No. of Axes Worst ase Shortest Executable 6ms 4ms ms 6ms 3 ms 8ms Publication 77-UMA EN P May

79 hapter 4 General Two example programs are presented in this chapter. The purpose of these programs is to illustrate the procedure and documentation that should be used and to explain the relationship between the ladder diagram program, positioning profile(s) and move data. -Axis Program The ladder diagram program presented in this section is written for a -axis machine application having a positioning profile of moves. Values for ramp time, final rate, decel time and final position for each move can be programmed using an industrial terminal and a Mini-PL-/ or PL-/3 programmable controller in a local or remote system configuration. The program would have to be modified (substitute multiple get/put instructions for file-to-file move instructions) in order to use a PL-/ controller. The following operational functions can be selected when programming the positioning profile. ontrolled stop Reset Initialization preset Software jog forward Software jog reverse Jog rate Type of profile Profile length Profiles that are longer than moves (one moveset) can be programmed by adding movesets. This can be done by programming additional file-to-file move instructions and entering move data in their corresponding files. Also, user-supplied inputs to the pulse output expander module can provide the following options: Hardware jog forward Hardware jog reverse Hardware stop (E-Stop) The program is written for a -axis machine application and requires one Stepper ontroller Module (cat. no. 77-M) and one Pulse Output Expander Module (cat. no. 77-OJ). The user-supplied stepper translator that interfaces with the pulse output expander module should accept low true inputs. Publication 77-UMA EN P May

80 4 Example Programs Programming a -Axis Profile The task of programming can be simplified by documenting the desired positioning profile in the following manner.. Sketch the positioning profile and designate the ramp time, final rate, final position, and decel values as needed (Figure 4.). Decide which of the three operating modes (continuous, independent or single step) should be used. Figure 4. Example -Axis Profile (ontinuous Mode) RT= 3. Sec FR= P/Sec FR=8 P/Sec Moves 8 RT=. Sec FR= P/Sec FR= P/Sec Reverse Forward FR=8 P/Sec FR= P/Sec FR= P/Sec Move # 3 4 FR= P/Sec Move RT= FR= P/Sec 3. Sec RT=. Sec 6 Position. Log all move data such as ramp time, final rate, final positions and decel values as needed, and offset/preset data if used. Use the Moveset Data form found at the end of this manual for each positioning profile moveset (Figure 4.) or jog moveset (Figure 4.3). 3. Write the ladder diagram program using the example as a guide (Figure 4.4). 4. Enter move data into corresponding data table files associated with file A of each file-to-file move instruction using the data monitor mode of the industrial terminal (Figure 4.). File R displays the data moved to the write block transfer file during operation and should be ignored during programming. Publication 77-UMA EN P May

81 Example Programs 4 3 Figure 4. Example -Axis Profile Moveset ALLEN-BRADLEY Programmable ontroller Moveset Data (October, 98) HEXIDEIMAL DATA MONITOR FILE TO FILE MOVE ounter Addr: 33 Axis No.: File Length: 64 File A: 4 to 477 Moveset No.: File R: to 77 Position FILE A DATA Description Move 3 MW Offset MS Preset LS Preset Decel Decel Decel Decel Decel 3 4 Position FILE A DATA Description Move Decel Decel Decel Decel Decel Publication 77-UMA EN P May

82 4 4 Example Programs Figure 4.3 Example Jog Moveset with Preset Data ALLEN-BRADLEY Programmable ontroller Moveset Data (October, 98) HEXIDEIMAL DATA MONITOR FILE TO FILE MOVE ounter Addr: 3 Axis No.: File Length: File A: 3 to 3 Moveset No.: File R: to Position FILE A DATA Description Move MW Offset MS Preset LS Preset Decel Position FILE A DATA Description Move Decel Decel 7 6 Publication 77-UMA EN P May

83 Example Programs 4 Figure 4.4 Example -Axis Program LADDER DIAGRAM DUMP START Stop (ontrolled) 6 Stop (ontrolled) 7 Reset Start Initialize Preset Jog Forward 3 7 Unlatch Jog Forward U OFF 8 Jog Reverse Unlatch Jog Reversed Hz Jog H Jog z U OFF Publication 77-UMA EN P May

84 4 6 Example Programs 6 Jog and Preset Data FILE TO FILE MOVE OUNTER ADDR: POSITION: FILE LENGTH: FILE A: FILE R: RATE PER SAN EN 7 36 DN 3 4 Profile Data FILE TO FILE MOVE OUNTER ADDR: POSITION: FILE LENGTH: FILE A: FILE R: RATE PER SAN EN 7 33 DN BLOK XFER READ DATA ADDR: MODULE ADDR: BLOK LENGTH: FILE: EN 7 4 DN Buffer Status Words FILE TO FILE MOVE OUNTER ADDR: POSITION: FILE LENGTH: FILE A: FILE R: RATE PER SAN EN 7 34 DN BLOK XFER WRITE DATA ADDR: MODULE ADDR: BLOK LENGTH: FILE: EN 6 4 DN Block Transfer Time Out 3 TON. PR 3 A L OFF [ G ] [ G ] [ G ] Display Only Publication 77-UMA EN P May

85 Example Programs 4 7 Figure 4. Example Data Monitor Display and Moveset Data HEXADEIMAL DATA MONITOR FILE-TO-FILE MOVE POSITION: ounter Addr: 33 File Length: 64 File A : File R: -77 Position File A Data File R Data MOVE MOVE MOVE MOVE Publication 77-UMA EN P May

86 4 8 Example Programs Position File A Data File R Data 9 3 MOVE MOVE MOVE MOVE MOVE MOVE Publication 77-UMA EN P May

87 Example Programs 4 9 Preset and Jog Data Preset and jog data are programmed in a -word moveset. The moveset data is contained in words 3-3 of the file-to-file move instruction having counter address 36 as shown in rung (Figure 4.4). The preset and jog data have been logged on the Moveset Data form (Figure 4.3). The function of the data is summarized in Table 4.A. Important: Bits in the moveset control word and single move control word have been set in hexadecimal notation for convenience so that move data can be entered in decimal numbers. The equivalence between hexadecimal and binary must be known. Otherwise, the binary data monitor mode would have to be used separately for setting bit patterns in the control words. Table 4.A Functions of Jog/Preset Data (-Axis Program) Position Number Equivalent Word Word Description Function 3 Moveset ontrol word Bit is set to identify axis. (The hex value of = in bits -, respectively.) 3 Offset Word Ignored in this example 3, 4 3, 33 ML, LS Preset Words Preset of 34 Single Move ontrol Word Bit 3 is set to identify the moveset as jog data. Bits 6 & 7 are set to identify the single move control word. 6 3 Time. second to accelerate to final rate 7 36 Final pulses/second or pulses/second depending on the bit pattern programmed in rungs and Decel Time. second to decelerate from final rate to zero. 9, 3. 3 Final Position of the jog 999,999 pulses. Allows maximum travel of the jog move if/as needed. This could also be programmed as,. Position number of the data monitor display of FFM 36. Equivalent words in file A of FFM 36. Publication 77-UMA EN P May

88 4 Example Programs Move Data The -move -axis positioning profile (Figure 4.) is in the continuous mode, reverses direction at 9, pulses and returns to the starting position. In order to reverse direction in this mode, a Hz rate move must be programmed (move 9). Note that decel values for all moves except the last move are ignored by the stepper controller module unless a software controlled stop is initiated, or a system fault is detected. Moveset data for the -axis profile is logged in the Moveset Data form (Figure 4.). When this data is entered into file A of the file-to-file move instruction FFM 33 using the data monitor mode of the industrial terminal, it will appear as in Figure 4.. File R should be ignored during programming. The functions of the moveset data are summarized in Table 4.B. Table 4.B Functions of Moveset Data (-Axis Program) Position Number Equivalent Word Word Description Function 4 Moveset ontrol Word Bit is set to identify axis. (The hex value of = in bits -, respectively.) Bits and are to designate continuous mode Offset/Preset Word Ignored in this example 44 Single Move ontrol Word hex = which identifies the single move control word for move. 6 4 Time 3. seconds to reach the final rate for move Final pulses/second, move Decel. second (only used if needed for an emergency controlled stop during mode.) MS, ition 6 pulses. Final position of move Repeated Move Data Move through move 8 (Each move is formatted similar to positions - for move ) hex. This begins the Hz rate move, move Time zero Publication 77-UMA EN P May

89 Example Programs 4 Position Number Equivalent Word Word Description Function 466 Final zero (ignored by stepper controller module) Decel Time. seconds (only used if needed for controlled stop) Final Position 9, pulses. The position where the final rate is zero hex. This begins the return move, move Time. seconds to reach final rate in reverse Final pulses/second in reverse Decel 3. seconds required value in last move. 63, , 477 MS. ition, pulses (starting position). Position number of the data monitor display of FFM 33. Equivalent words in file A of FFM 33. Ladder Diagram -Axis Program An example ladder diagram program for a -axis profile is presented in Figure 4.4. A description of each rung follows: Rungs and These rungs provide a controlled stop. When bit / is true, bit /6 (moveset control word, stop bit) is true and bit /7 (moveset control word, decel/inst bit) is true. The stepper controller module will perform a controlled stop using the decel value in the move being processed at the time the stop command is received. Rung 3 This rung provides a reset (i.e. clears all status and position information) to re-initialize the stepper controller module. When bit /3 is true, bit /4 (moveset control word, reset bit) is true. Therefore, the controller module is rest. Rung 4 This rung is used to start the positioning profile. When bit /4 is true, bit / (moveset control word, start bit) is true. Execution of the positioning profile begins. Rung This rung provides an initialized preset. When bit /6 is true, bit /7 (most significant preset word, bit 7) is true. Therefore, a preset is performed. Publication 77-UMA EN P May

90 4 Example Programs Rungs 6 and 7 These rungs start and stop a jog forward move. When bit / is true, bit 3/ (moveset control word, jog forward bit) is true and a jog forward is initiated. When bit / is false, the jog forward bit (bit /) will be unlatched and jog motion will cease. Rungs 8 and 9 These rungs start and stop a jog reverse move. When bit / is true, bit 3/4 (moveset control word, jog reverse bit) is true and a jog reverse is initiated. When bit / is false, the jog reverse bit (bit /4) will be unlatched and jog motion will cease. Rung This rung allows a jog rate of Hz to be selected. When bit / is false, bit 36/4 is true (word 36 contains rate data) and a rate of Hz is selected. Rung This rung allows a jog rate of Hz to be selected. When bit / is true, bit 36/4 is true and a jog rate of Hz is selected. Rung This rung contains the file-to-file move instruction which stores the preset and jog data. The preset data is stored in word 33 and jog data in words File A (containing preset and jog data) will be transferred to the stepper controller module each time a false-to-true transition occurs. Note that file R (-) is the first words of the write block transfer file in rung 6. Each time a jog forward (/), jog reverse (/) or initialization preset (/6) is requested, the contents of file A will be sent to the stepper controller module. Note that the preset data sent with every jog forward or jog reverse has no effect, since bit /7 is false (rung ). Rung 3 This rung contains the file-to-file move instruction which stores the positioning profile. This particular profile consists of moves requiring a 64-word file (4-477). When bit /4 is true the positioning profile (4-477) will be moved to file R (-77) and transferred to the stepper controller module. Publication 77-UMA EN P May

91 Example Programs 4 3 Rung 4 This rung contains the block transfer read instruction that receives status from the stepper controller module in rack, module group 4, slot. The block length is selected as (default value). As such, the maximum number of words that the stepper controller module will transfer to the P processor will depend on the highest address of the pulse output expander module(s) in the chassis: Ten for address 3, seven for address or four for address. In this example, only four words of status will be read. Words 4-77 can be used for other programming. Rung This rung contains the file-to-file move instruction that buffers the first four words of status data from the block transfer read file. Each time the read block transfer done bit (4/7) is true, the contents of file A (-3) will be sent to file R (-3). Buffering is necessary when operating in an electrical noise environment to ensure data integrity. Rung 6 This rung contains a block transfer write instruction which transfers preset, jog and profile data to the stepper controller module. The block length is 64 words (default, ) equal to the largest file to be transferred to the stepper controller module. The block transfer write file need not be buffered since buffering is done internally by the stepper controller module. Rungs 7 and 8 These are block transfer time-out rungs. If a block transfer is not completed within 3 seconds, then output /6 will be latched on. This output can be used to energize a warning device. Rung 9 This rung displays the status of axis. Word is reserved for future use, word is the status word, word is the MS position value and word 3 is the LS position value. This rung is for display only and has no effect on program operation. Important: Reset word 3 to zero as a boundary between block transfer and other instruction addresses. Operational Summary After the ladder diagram program is written, the data monitor mode of the industrial terminal can be used to enter move data into the data table files which are controlled by the file-to-file move (FFM) instructions. FFM 36 rung Preset and jog data FFM 33 rung 3 Moveset data for the positioning profile Publication 77-UMA EN P May

92 4 4 Example Programs ommands are transferred to the stepper controller module by setting a bit in either the moveset control word, single move control word or MS preset word. The command bit can be set when the control word is in either of two locations: in file A of file-to-file move instructions FFM 36 or FFM 33, or in the write block transfer file R (-77) where data resides momentarily when transferred to the stepper controller module. When programming a -axis profile, either can be used. When programming a -axis or 3-axis profile, bits should be set in file A of the file-to-file move instruction, not in file R. The jog moveset containing preset data can be block transferred to the stepper controller module with either a software jog forward or jog reverse command or an initialization preset command. This can be done when rung and either rung,6, or 8 are true in the same scan. In this case the initialization preset command, bit 7 of the MS preset word, is set in file R (/7). The software jog forward or jog reverse command, bit or 4 respectively in the moveset control word, is set in file A (FFM 36). The start command for the positioning profile can be block transferred to the stepper controller module simultaneously with the positioning profile moveset. This can be done when rungs 4 and 3 are true in the same scan. In this case, the start bit, bit of the moveset control word, is set in file R (/). The positioning profile will then be executed independent of the P processor scan, once the stepper controller module has received the data. The other functions such as stop, reset or jog fwd/rev can be initiated by energizing the appropriate bits in rungs -. The stop and reset commands can be initiated any time during a positioning sequence, whereas the initialization preset and jog forward or jog reverse commands can only be initiated before or after a positioning sequence. The status information received from the stepper controller module by a read block transfer (rung 4) is buffered by the file-to-file move instruction in rung. This is necessary to ensure data integrity particularly when operating in any electrical noise environment. The write block transfer data in rung 6 need not be buffered by user program because the stepper controller module buffers write data internally. Rungs 7 and 8 are block transfer time-out rungs. If a write block transfer is not completed within three seconds, output /6 will be latched on. This can be used to illuminate a warning lamp, etc. Rung 9 displays status information and has no effect on program operation. Publication 77-UMA EN P May

93 Example Programs 4 3-Axis Program The ladder diagram program presented in this section is written for a 3-axis machine operation where each axis has a different -move continuous mode positioning profile. Sketches of the three profiles are shown in Figure 4.6. A detailed profile for each axis is shown in Figure 4.7, Figure 4.8 and Figure 4.9. The 3-axis system requires that one Stepper ontroller Module (cat. no. 77-M) and three Pulse Output Expander Modules (cat. no. 77-OJ) be used in the same I/O chassis. The operational functions and hardware input options are generally the same as the -axis program described in section 4.. It is assumed that an industrial terminal and either a Mini-PL-/ or PL-/3 programmable controller are being used. Figure 4.6 Example 3-Axis Profile (ontinuous Mode) K K Axis # k k 3k 4k k 6k 7k 8k 9k k k k 3k 4k k 6k 7k 8k RT=3. Sec Move -8 Time =. Sec Move 9 is a Hz Move k k k Move 9 k 3k RT=3. Sec Move K K Axis # k k 3k 4k k 6k RT=. Sec Move Moves 9 7k 8k RT=. Sec Move -8 Time =. Sec Move 9 is a Hz Move K K 3 kk3k 4k k 6k 7k 8k 9k k k k 3k RT=. Sec Axis #3 Move -8 Time =. Sec Move 9 is a Hz Move 4 Move k k 6k 7k 8k 9k k k k 3k Move RT=. Sec 6 Publication 77-UMA EN P May

94 4 6 Example Programs Figure 4.7 Axis of Example 3-Axis Profile RT=. Sec FR= P/Sec FR=9 P/Sec FR=9 P/Sec FR=8 P/Sec FR=8 P/Sec FR=7 P/Sec FR=6 P/Sec FR=7 P/Sec FR=6 P/Sec FR= P/Sec Moves 8 RT=. Sec FR= P/Sec FR=4 P/Sec Forward Reverse FR=4 P/Sec FR=3 P/Sec FR=3 P/Sec FR= FR= P/Sec P/Sec FR= P/Sec DT=3. Sec 8 RT=3. Sec FR= P/S Move Hz Move Position Publication 77-UMA EN P May

95 Example Programs 4 7 Forward RT=. Sec FR= P/Sec FR=4 P/Sec FR=4 P/Sec 3 FR=3 P/Sec Figure 4.8 Axis of Example 3-Axis Profile FR=3 P/Sec FR=4 P/S FR= P/Sec FR= P/Sec FR= P/Sec FR=4 P/S FR= P/Sec FR= P/S FR=3 P/S FR=3 P/S Moves 8 RT=. Sec FR= P/S FR= P/S FR= P/S FR= P/S Position Reverse DT=. Sec Move RT=. Sec FR= P/S Hz Move 69 Publication 77-UMA EN P May

96 4 8 Example Programs Figure 4.9 Axis 3 of Example 3-Axis Profile FR= P/S Forward Reverse RT=. Sec Position 8 98 DT=. Sec FR=9 P/S FR=8 P/S FR=7 P/S FR=6 P/S FR= P/S FR=4 P/S 7 FR= P/Sec FR=4 P/S 8 FR=3 P/S FR=3 P/S 9 Moves 8 RT=. Sec FR=7 P/S FR= P/S FR= P/S FR= P/S FR=7 P/S Move FR= P/S FR= P/S FR= P/S 9 3 RT=. Sec Position 37 Hz Move 68 Programming a 3-Axis Profile The documentation and procedures for programming a 3-axis program are similar to those of the -axis program described in section titled -Axis Program. The 3-axis ladder diagram program presented in this section shows an alternate approach to organizing preset and jog data, and for transferring commands to the stepper controller module. A 4-word command file has been programmed using a file-to-file move instruction for each axis. The command file contains the moveset control word, offset and preset words. ommands with accompanying offset and preset data can be transferred to the stepper controller module without jog data. A separate jog moveset stored in a file-to-file move instruction for each axis simplifies the ladder diagram program and associated record keeping of command, jog, and profile moveset data. Publication 77-UMA EN P May

97 Example Programs 4 9 Also note that command bits for each axis are set in the corresponding control word in file A of the file-to-file move instruction prior to transfer to the stepper controller module. ommand bits are not set in the write block transfer file, file R, as can be done in a -axis program. Each axis is programmed for moves. Therefore two -move 64 word profile movesets must be programmed for each axis. The first profile moveset for each axis is labeled, the second is labeled by MW, bit 6. Be sure that the axis to receive data is specified by correctly setting the address bits and in the corresponding moveset control words. Note that a false-to-true transition of any file-to-file move instruction (rungs of Figure 4.) controlling profile movesets will cause motion in the corresponding axis. This is because the start bit (bit ) of the moveset control word was initially set in each profile moveset. The ladder diagram program for the example 3-axis program is presented in Figure 4.. orresponding moveset data has been logged on the Moveset Data forms. These forms contain the data for the example command files (Figures 4., 4. and 4.3), example jog movesets (Figures 4.4, 4. and 4.6), and example profile movesets and (Figures 4.7 thru 4.) for each of the three axes. A description of each rung of the 3-axis ladder diagram program follows: Important: Reset word 3 to zero as a boundary between block transfer and other instruction addresses. Publication 77-UMA EN P May

98 4 Example Programs Figure 4. Example 3-Axis Program LADDER DIAGRAM DUMP START Stop Axis 6 6 Stop Axis 6 7 Reset Axis 7 4 Initialize Preset Axis Jog Forward Axis Unlatch Jog Forward Axis 3 U 4 OFF Jog Reverse Axis 4 Unlatch Jog Reverse Axis 3 U OFF 4 Offset Axis 4 3 Stop Axis 4 6 Stop Axis 4 7 Reset Axis Initialize Preset Axis Jog Forward Axis 4 4 Publication 77-UMA EN P May

99 Example Programs Unlatch Jog Forward Axis 3 U OFF Jog Reverse Axis 4 4 Unlatch Jog Reverse Axis 3 U OFF 4 Offset Axis Stop Axis Stop Axis Reset Axis Initialize Preset Axis Jog Forward Axis 3 36 Unlatch Jog Forward Axis 3 3 U 4 OFF Jog Reverse Axis Unlatch Jog Reverse Axis 3 3 U OFF 4 7 Offset Axis Publication 77-UMA EN P May

100 4 Example Programs ommand File (Includes Offset and Preset Data) Axis FILE TO FILE MOVE OUNTER ADDR: POSITION: FILE LENGTH: FILE A: FILE R: RATE PER SAN EN 7 3 DN ommand File (Includes Offset and Preset Data) Axis FILE TO FILE MOVE OUNTER ADDR: POSITION: FILE LENGTH: FILE A: FILE R: RATE PER SAN EN 7 36 DN ommand File (Includes Offset and Preset Data) Axis 3 FILE TO FILE MOVE OUNTER ADDR: POSITION: FILE LENGTH: FILE A: FILE R: RATE PER SAN EN 7 37 DN 3 Jog Data Axis FILE TO FILE MOVE OUNTER ADDR: POSITION: FILE LENGTH: FILE A: FILE R: RATE PER SAN EN 7 DN Publication 77-UMA EN P May

101 Example Programs Jog Data Axis FILE TO FILE MOVE OUNTER ADDR: 4 POSITION: FILE LENGTH: FILE A: FILE R: RATE PER SAN EN 7 4 DN 33 Jog Data Axis 3 FILE TO FILE MOVE OUNTER ADDR: 43 POSITION: FILE LENGTH: FILE A: FILE R: RATE PER SAN EN 7 43 DN 34 4 Moveset (Axis ) FILE TO FILE MOVE OUNTER ADDR: 33 POSITION: FILE LENGTH: 64 FILE A: FILE R: RATE PER SAN EN 7 33 DN 3 Moveset (Axis ) FILE TO FILE MOVE OUNTER ADDR: 4 POSITION: FILE LENGTH: 64 FILE A: FILE R: RATE PER SAN EN 7 4 DN 36 Moveset (Axis 3) FILE TO FILE MOVE OUNTER ADDR: 44 POSITION: FILE LENGTH: 64 FILE A: FILE R: RATE PER SAN EN 7 44 DN Publication 77-UMA EN P May

102 4 4 Example Programs 37 6 Moveset (Axis ) FILE TO FILE MOVE OUNTER ADDR: 34 POSITION: FILE LENGTH: 64 FILE A: FILE R: RATE PER SAN EN 7 34 DN Moveset (Axis ) FILE TO FILE MOVE OUNTER ADDR: 4 POSITION: FILE LENGTH: 64 FILE A: FILE R: RATE PER SAN EN 7 4 DN Moveset (Axis 3) FILE TO FILE MOVE OUNTER ADDR: 4 POSITION: FILE LENGTH: 64 FILE A: FILE R: RATE PER SAN EN 7 4 DN BLOK XFER READ DATA ADDR: 3 MODULE ADDR: 4 BLOK LENGTH: FILE: 77 4 EN 7 4 DN Buffer Status Words FILE TO FILE MOVE 47 OUNTER ADDR: 47 EN POSITION: FILE LENGTH: 7 FILE A: 47 FILE R: 6 RATE PER SAN DN BLOK XFER WRITE DATA ADDR: 3 MODULE ADDR: 4 BLOK LENGTH: FILE: EN 6 4 DN 6 Publication 77-UMA EN P May

103 Example Programs [ G ] [ G ] 3 [ G ] Axis Block Transfer Time Out 46 TON. PR 3 A L OFF [ G ] [ G ] 6 [ G ] Axis > For Display Only 47 7 [ G ] 6 [ G ] 6 [ G ] Axis 3 Publication 77-UMA EN P May

104 4 6 Example Programs Figure 4. Example ommand File, Axis ALLEN-BRADLEY Programmable ontroller Moveset Data (October, 98) HEXIDEIMAL DATA MONITOR FILE TO FILE MOVE ounter Addr: 3 Axis No.: File Length: 4 File A: to Moveset No.: File R: 3 to 33 Position FILE A DATA Description Move 3 4 MW Offset MS Preset LS Preset Position FILE A DATA Description Move Figure 4. Example ommand File, Axis ALLEN-BRADLEY Programmable ontroller Moveset Data (October, 98) HEXIDEIMAL DATA MONITOR FILE TO FILE MOVE ounter Addr: 36 Axis No.: File Length: 4 File A: 4 to 7 Moveset No.: File R: 3 to 33 Position FILE A DATA Description Move 3 4 MW Offset MS Preset LS Preset Position FILE A DATA Description Move Publication 77-UMA EN P May

105 Example Programs 4 7 Figure 4.3 Example ommand File, Axis 3 ALLEN-BRADLEY Programmable ontroller Moveset Data (October, 98) HEXIDEIMAL DATA MONITOR FILE TO FILE MOVE ounter Addr: 37 Axis No.: 3 File Length: 4 File A: 36 to 4 Moveset No.: File R: 3 to 33 Position FILE A DATA Description Move MW Offset MS Preset LS Preset Position FILE A DATA Description Move Figure 4.4 Example Jog Moveset, Axis ALLEN-BRADLEY Programmable ontroller Moveset Data (October, 98) HEXIDEIMAL DATA MONITOR FILE TO FILE MOVE ounter Addr: 3 Axis No.: File Length: File A: to 3 Moveset No.: File R: 3 to 3 Position FILE A DATA Description Move MW Offset MS Preset LS Preset 7 8 Decel Position FILE A DATA Description Move Decel Decel 7 69 Publication 77-UMA EN P May

106 4 8 Example Programs Figure 4. Example Jog Moveset, Axis ALLEN-BRADLEY Programmable ontroller Moveset Data (October, 98) HEXIDEIMAL DATA MONITOR FILE TO FILE MOVE ounter Addr: 4 Axis No.: File Length: File A: 4 to 3 Moveset No.: File R: 3 to 3 Position FILE A DATA Description Move MW Offset MS Preset LS Preset 7 8 Dece; Position FILE A DATA Description Move Decel Decel 7 6 Publication 77-UMA EN P May

107 Example Programs 4 9 Figure 4.6 Example Jog Moveset, Axis 3 ALLEN-BRADLEY Programmable ontroller Moveset Data (October, 98) HEXIDEIMAL DATA MONITOR FILE TO FILE MOVE ounter Addr: 43 Axis No.: 3 File Length: File A: 36 to 47 Moveset No.: File R: 3 to 3 Position FILE A DATA Description Move MW Offset MS Preset LS Preset Dece; Position FILE A DATA Description Move Decel Decel 7 6 Publication 77-UMA EN P May

108 4 3 Example Programs Figure 4.7 Example Profile Moveset, Axis ALLEN-BRADLEY Programmable ontroller Moveset Data (October, 98) HEXIDEIMAL DATA MONITOR FILE TO FILE MOVE ounter Addr: 33 Axis No.: File Length: 64 File A: 4 to 477 Moveset No.: File R: 3 to 377 Position FILE A DATA Description Move 4 MW Offset MS Preset LS Preset Decel Decel Decel Decel Decel 3 4 Position FILE A DATA Description Move Decel Decel Decel Decel Decel Publication 77-UMA EN P May

109 Example Programs 4 3 Figure 4.8 Example Profile Moveset Axis ALLEN-BRADLEY Programmable ontroller Moveset Data (October, 98) HEXIDEIMAL DATA MONITOR FILE TO FILE MOVE ounter Addr: 34 Axis No.: File Length: 64 File A: to 77 Moveset No.: File R: 3 to 377 Position FILE A DATA Description Move MW Offset MS Preset LS Preset Decel Decel Decel Decel Decel 3 4 Position FILE A DATA Description Move Decel Decel Decel Decel Decel Publication 77-UMA EN P May

110 4 3 Example Programs Figure 4.9 Example Profile Moveset, Axis ALLEN-BRADLEY Programmable ontroller Moveset Data (October, 98) HEXIDEIMAL DATA MONITOR FILE TO FILE MOVE ounter Addr: 4 Axis No.: File Length: 64 File A: 6 to 677 Moveset No.: File R: 3 to 377 Position FILE A DATA Description Move 4 MW Offset MS Preset LS Preset Decel Decel Decel Decel Decel 3 4 Position FILE A DATA Description Move Decel Decel Decel Decel Decel Publication 77-UMA EN P May

111 Example Programs 4 33 Figure 4. Example Profile Moveset O, Axis ALLEN-BRADLEY Programmable ontroller Moveset Data (October, 98) HEXIDEIMAL DATA MONITOR FILE TO FILE MOVE ounter Addr: 4 Axis No.: File Length: 64 File A: 7 to 777 Moveset No.: File R: 3 to 377 Position FILE A DATA Description Move MW Offset MS Preset LS Preset 4 Decel Decel Decel Decel Decel 3 4 Position FILE A DATA Description Move Decel Decel Decel Decel Decel Publication 77-UMA EN P May

112 4 34 Example Programs Figure 4. Example Profile Moveset, Axis 3 ALLEN-BRADLEY Programmable ontroller Moveset Data (October, 98) HEXIDEIMAL DATA MONITOR FILE TO FILE MOVE ounter Addr: 44 Axis No.: 3 File Length: 64 File A: to 77 Moveset No.: File R: 3 to 377 Position FILE A DATA Description Move MW Offset MS Preset LS Preset Decel Decel Decel Decel Decel 3 4 Position FILE A DATA Description Move Decel Decel Decel Decel Decel Publication 77-UMA EN P May

113 Example Programs 4 3 Figure 4. Example Profile Moveset Axis 3 ALLEN-BRADLEY Programmable ontroller Moveset Data (October, 98) HEXIDEIMAL DATA MONITOR FILE TO FILE MOVE ounter Addr: 4 Axis No.: 3 File Length: 64 File A: to 77 Moveset No.: File R: 3 to 377 Position FILE A DATA Description Move 3 3 MW Offset MS Preset LS Preset 7 Decel Decel Decel Decel Decel 3 4 Position FILE A DATA Description Move Decel Decel Decel Decel Decel Publication 77-UMA EN P May

114 4 36 Example Programs Rungs and ontrolled stop rungs for axis. When user input /6 is energized, bit /6 (MW, stop bit) and /7 (MW, decl/inst bit) are high and the contents of the file-to-file move instruction in rung 8 are transferred to the stepper controller module. The stepper controller module will perform a controlled stop using the decel value in the move being processed at the time the stop command is received. Rung 3 Reset rung for axis. When user input /7 is energized, bit /4 (MW, reset bit) is high and the contents of the file-to-file move instruction in rung 8 is transferred to the stepper controller module. All status, position and move data for axis is cleared from the memory of the stepper controller module. Rung 4 Initialization preset rung for axis. When user input /7 is energized, bit 4/7 (MS preset word, assert bit) is high and the contents of the file-to-file move instruction in rung 8 is transferred to the stepper controller module. Axis will be preset according to the number of pulses programmed in the MS and LS preset words (words 4 and ). Rungs and 6 Jog forward rungs for axis. When user input / is energized, bit / (MW, jog forward bit) is true and the jog data contained in the file-to-file move instruction in rung 3 is transferred to the stepper controller module. Axis will jog forward until bit / is de-energized (i.e. user releases pushbutton). When bit / is de-energized (rung 6), and the jog forward inputs for axis (/4) and axis 3 (/) are false, then axis will decel to Hz according to the decel value programmed in word (file-to-file move instruction, rung 3). Rungs 7 and 8 Jog reverse rungs for axis. When user input / is energized, bit /4 (MW, jog reverse bit) is true and the jog data contained in the file-to-file move instruction in rung 3 is transferred to the stepper controller module. Axis will jog forward until bit / is de-energized and the jog reverse inputs for axis and axis 3 are false (rung 8). Axis will decel to Hz according to the decel value programmed in word (file-to-file move instruction, rung 3). Publication 77-UMA EN P May

115 Example Programs 4 37 Rung 9 Offset rung for axis. When user input /4 is energized, bit /3 (MW, offset bit) is true and the number of pulses programmed in offset word 3 (file-to-file move instruction, rung 8) will be added or subtracted to the final position of each move according to the state of bit 3/7 (subtract/add offset bit). Refer to Offset Word in chapter 3. Rungs thru 7 Stop, reset, initialization preset, jog forward, jog reverse and offset rungs for axis and axis 3. These rungs function exactly the same as rungs -9. However, the addresses are different since they pertain to different axes. Rung 8 ommand file rung for axis (includes offset and preset data). Each time a false-to-true transition caused by a controlled stop (/6), reset (/7), initialization preset (/7) or offset (/4) occurs, file A (-) will be transferred to file R (3-33), which is the write block transfer file. Rungs 9 and 3 Same function as rung 8, but for axis and axis 3. Rung 3 Jog rung for axis. Each time a false-to-true transition caused by a jog forward (/) or jog reverse (/) occurs, jog data in words -3 is transferred to the stepper controller module. Rungs 3 and 33 Same function as rung 3, but for axis and axis 3. Rung 34 Profile data (moves -) for axis is stored in file A (4-477). When bit /4 is energized, file A (4-477) will be transferred to the stepper controller module. Since the start bit is already set in word 4 (MW, bit ), the profile is immediately started. Rungs 3 and 36 Same function as rung 34, but for axis and axis 3. Publication 77-UMA EN P May

116 4 38 Example Programs Rung 37 When the first profile moveset is sent to the stepper controller module (rung 4), bit 6 of status word will toggle. When bit /6 toggles, a false-to-true transition in rung 37 occurs and the second profile moveset is transferred to the stepper controller module and is stored in the buffer associated with that axis. The second profile moveset (moves -) for axis is stored in file A (-77). The second moveset is blended automatically with the first moveset to create a -move profile (continuous mode). Note that bit 6 of the MW (moveset bit) for the first profile moveset is true and for the second moveset is false. Therefore, the profile for axis consists of a moveset followed by a moveset. Rungs 38 and 39 Same function as rung 37, but for axis and axis 3. Rung 4 Block transfer read rung. The module is located in rack, module group 4, slot. The block length is set by the default value,. The stepper controller module will automatically send the required status words (four words for axis, seven words for axes and ten words for 3 axes) depending on the highest numbered expander addresses in the chassis. Since the stepper controller module will only send back a maximum of ten status words, the remaining words -77 can be used for other purposes. Rung 4 This rung contains a file-to-file move instruction which buffers status data from the block transfer read file (-). Each time the read block transfer done bit (4/7) is true, the contents of file A (-) will be sent to file R (-6). The done bit will be set only after the transfer and received data have been validated by the P processor. Rung 4 The rung contains a block transfer write instruction which sends commands, jog data and profile data to the controller module. The block length is set to 64 words by the default value. The block transfer write file need not be buffered since the buffering is done internally by the controller module. Rung 43 and 44 Block transfer time-out rungs. if a block transfer is not completed within 3 seconds, output /6 will be latched on. This output can be used to energize a warning device. Publication 77-UMA EN P May

117 Example Programs 4 39 Rungs 4 thru 47 These rungs display the status of axes,, and 3. Word is reserved for future use, word is the status word for axis, word is the MS position value for axis and word 3 is the LS position value for axis. The relationship applies to words 4-6 (axis ) and words 7-6 (axis 3). Operational Summary After the ladder diagram program has been written, the appropriate move data can be entered in the file-to-file move instructions in rungs This can be done using the data monitor display mode of the industrial terminal. With P processor in program mode, place the cursor on the file-to-file move instruction and press [DISPLAY][]. Move data can be conveniently entered in hexadecimal notation. The equivalency between hexadecimal and binary must be known when setting bits in control words. When rungs 34, 3 and 36 undergo a false-to-true transition, the positioning profile of axes, and 3, respectively, begins execution. As soon as the first moveset (moveset ) of an axis is transferred to the stepper controller module, the corresponding moveset status bit (status word, bit 6) will toggle and cause the next moveset (moveset ) to be transferred (rung 37, 38 or 39). After an axis has completed its last move, the moveset sequence can be repeated by another false-to-true transition of rung 34, 3 or 36. ommands such as stop, start, reset, initialization preset, jog forward, jog reverse and offset for any of the axes can be initiated by enabling the appropriate rung (rungs -7). Note that for this 3-axis example, only one axis can be jogged at a time (rungs 6, 8,, 7, 4, 6). The status information received from the stepper controller module by read block transfer (rung 4) is buffered by a file-to-file move instruction (rung 4). The validated data ( words) is then stored in words -6. Read block transfer data should be buffered when operating in an environment where electrical noise is present. As a precautionary measure, if a write block transfer is not done within 3 seconds, an output is latched on (rung 43). This output can be used to energize a warning device. Status information is displayed in rung 4: words -3 for axis, words 4-6 for axis and words 7-6 for axis 3. Rung 4 has no effect on program operation. During debugging of a positioning program, operate the system with the stepper translator and motor assembly disconnected until any programming errors and/or system faults have been corrected. Publication 77-UMA EN P May

118 4 4 Example Programs ALLEN-BRADLEY Programmable ontroller Moveset Data (October, 98) HEXIDEIMAL DATA MONITOR FILE TO FILE MOVE ounter Addr: Axis No.: File Length: File A: to Moveset No.: File R: to Position FILE A DATA Description Move MW Offset 3 MS Preset 4 LS Preset Decel Decel Decel Decel Decel Position FILE A DATA Description Move Decel Decel Decel Decel Decel Publication 77-UMA EN P May

119 Example Programs 4 4 ALLEN BRADLEY Programmable ontroller DATA TABLE WORD MAP (4 WORD) (Publication 44 February, 98) PAGE ADDRESS OF TO PROJET NAME DESIGNER PROESSOR DATA TABLE SIZE WORD ADDRESS FROM (3 WORDS) TO WORD ADDRESS REF Publication 77-UMA EN P May

120 4 4 Example Programs Publication 77-UMA EN P May

121 hapter General A programming error will be reflected in the status word of the affected axis with the programming error bit set (bit 4). The systems fault bit in some cases will also be set. When the system fault bit is not set, programming errors can be cleared by transferring new error-free block transfer data of any length to that same axis. When new data or commands are appropriately acted upon by the stepper controller module, the programming error bit in the status word will be cleared. A stop or reset command can also be transferred to the stepper controller module to clear the error. When a system fault is detected by the stepper controller module with or without a programming error, the system fault bit (bit 3) will be set in the status word of the affected axis. When a system fault is detected, no additional move data will be sent by the stepper controller module to the pulse output expander module. onsequently at the end of the current move, the pulse output expander module would decelerate to Hz at the programmed decel value. A system fault can be cleared by a reset command, only. The global reset command (MW, bit 4 =, = ) is a convenient way to clear all previously loaded data for all axes. Troubleshooting Tables Troubleshooting tables for power-up (Table.A) and operation (Table.B) are found at the end of this section. The power-up troubleshooting table lists combination of LED indicators which will illuminate due to various faults and errors. Possible causes and corrective action are also listed. The most probable occurrences are listed first. The first LED combination listed shows the indicators when the stepper positioning assembly is operating normally. The operation troubleshooting table lists possible causes of programming errors and corresponding corrective action. Programming errors which do not cause a system fault are listed first (system fault bit 3 = ). Programming errors which cause a system fault (system fault bit 3 = ) are listed last. The most probable occurrences are listed ahead of less probable occurrences in both parts of this table. Publication 77-UMA EN P May

122 Troubleshooting Table.A Power-Up Troubleshooting Led Indication Possible ause orrective Action P OMM FAULT EXPANDER OMM FAULT ATIVE MODULE FAULT Normal Operation None F P OMM FAULT EXPANDER OMM FAULT ATIVE MODULE FAULT Expander address is incorrect. More than one 77-M module in the chassis No 77-OJ module in the chassis Switch 3 on 77-OJ module must be, or. Install only one 77-M module per chassis. Install at least one 77-OJ module per chassis. P OMM FAULT EXPANDER OMM FAULT ATIVE MODULE FAULT Block transfer error heck cables and adapters for faulty or intermittent operation. heck for invalid block transfer starting address. P OMM FAULT EXPANDER OMM FAULT ATIVE MODULE FAULT ommunications error between 77-M module and 77-OJ heck that all modules are properly installed in chassis. Noisy environment: check earth grounding of chassis power supplies, stepper motor/translator and noise sources (relays, motors, etc.) too close to the chassis. P OMM FAULT EXPANDER OMM FAULT ATIVE MODULE FAULT Hardware failure ycle power to chassis. If problem still exists, replace module. P OMM FAULT EXPANDER OMM FAULT ATIVE MODULE FAULT ommunications error between 77-M and 77-OJ modules Initialization error Watchdog timers timed-out See ORRETIVE ATION above for omm. Error between 77-M and 77-OJ modules. Hardware error, see above Hardware error, see above LED indicators on the stepper controller module LED indicator on the pulse output expander module Legend: ON OFF Flashing F Publication 77-UMA EN P May

123 Troubleshooting 3 Table.B Operation Troubleshooting Status Word Bits Programming Error, Bit 4 System Fault, Bit 3 Possible ause orrective Action Single move control word of one or more move blocks (except in a truncated or zeroed end portion of a moveset) does not have bits 7 and 6 = or bits -4 =. Bits 4-7 of ramp, decel, MS position and LS position words of move blocks are not reset. Bits 6-4 of MS preset and bits 7-4 of LS preset words are not reset. Illegal combination of command and/or control bits Initialization preset and/or software jog command attempted during a profile During a software jog, a command other than stop or reset was sent. Sent offset command with -word block transfer write Sent override command with one or four word block transfer write. Sent software jog command not accompanied by jog data following a reset Position value of a move in the profile is too small to allow msec of final rate. Final rate value of a move in the profile is too high to allow msec of final rate. Set or reset bits where required. heck moveset data for a missing or extra entry causing all other data to be shifted up or down. Reset bits (these bits must always be zero). Reset bits (these bits must always be zero). See Table. (Illegal Bit ombinations). Generally, only one command bit should be sent at a time. If the overset control word is programmed with an axis number of, 4,, 6, 7 or with a number for which there is no expander in the chassis, a programming error will be returned in the status word of all axes present. Must do either or both before a profile begins. Send command before or after the software jog. Block transfer write must be at least four words to include offset data. Override command must always be accompanied by at least a -move moveset to be executed as the override moveset. A power-up or software reset clears any previously loaded jog data in the module. Jog data must then accompany a jog command or be transferred prior to initiating a software or hardware jog. Examine the programmed move data of the next two moves following the move shown in the status word, if operating in the continuous mode or independent mode. If in the single step mode, examine the present move which was not executed or not executed properly. Use equations if necessary to find invalid data. Refer to section titled Application onsiderations in chapter 3. value or decel value (if normally executed) of a move in the profile is too large to allow msec of final rate. hange of direction attempted when not at Hz In the continuous mode, program a Hz rate move preceding the move that reverses direction. The Hz rate move is not needed or allowed in the independent or single step mode. Publication 77-UMA EN P May

124 4 Troubleshooting Programming Error, Bit 4 System Fault, Bit 3 Possible ause orrective Action Override ramp not acceptable The actual executed ramp time of the first move of an override moveset is generally not the value programmed. Refer to override ramp time text and equations section titled Decel and Position onsiderations for a Hz Move. Offset value, when added, causes a position value greater than 999,999 or, when subtracted, causes a position value less than. Hz rate move attempted in single step or independent move. Attempted to begin a move profile when the position in status block is negative possible caused by previous jog reverse command. Use an initialization preset before starting a profile, or initiate a move preset before the limit of 999,999 pulses is reached. Use the move preset again in order to return to the home position. Reprogram the move profile without the Hz rate move. After a reverse jog to a negative position, an initialization preset or a move preset in the first move block must be executed to start the profile at a positive position. A rest command can be used if the profile starts at. Hz rate move not acceptable Position values could be too small to allow msec of final rate, or too large which would cause the actual executed decel time to be greater than 9.99 seconds. Programmed ramp and decel times are ignored. Use Hz rate equations to check data. WHEN SYHRONIZING AXES Sent software jog or initialization preset command while one of the axes was executing a profile. Attempted to start a synchronized sequence with non-sync data or no data previously loaded to an axis. These commands can only be sent to an axis when all axes are at rest (not executing a profile). All axes must be loaded with sync data of the same mode or all axes with non-sync data. If desired, an axis or global reset will clear all data stored in the controller module for all axes. NOTE: If LEDs illuminate during operation, refer to appropriate LED combination in Table.A, Power-up Troubleshooting. Publication 77-UMA EN P May

125 Troubleshooting Illegal Bit ombinations ertain combinations of bits or an illegal bit state entered in the moveset control word, single move control word and/or MX preset word can cause a programming error. Refer to Table.. Moveset ontrol Word Table. Illegal Bit ombinations Single Move ontrol Word MS Preset Word Override Moveset Jog Forward Jog Reverse Offsest Axis Addr. Axis Addr. Decel/Inst. Stop Glbal/Axis Reset Synch. Axis Mode Select Mode Select Start Identification Identification Load Jog Skip Multiplier Move Preset Init. Preset Any of the above bit combinations are illegal in the same row 68 Publication 77-UMA EN P May

126 6 Troubleshooting Publication 77-UMA EN P May

127 Module Location Backplane Power Requirements Pulse Output Expander Module Specifications (cat. no. 77-OJ) Auxiliary Power Supply Requirements (V+) Input Delay Input Voltage Range On-State urrent per Input Output Voltage Range Maximum Output urrent Worst ase rise/fall time Bulletin 77 I/O Rack module slot, not address dependent 8mA, V dc NE lass listed + to +3V D 34mA max. Ripple: Not to exceed the input specification for the stepper translator JOG: 3ms (-axis) thru ms (3-axis) STOP: microseconds Minimum High State: +V supply -. volts. The module has a.6k ohm internal pull-up resistor. Therefore: ) Open collector logic devices are compatible ) Hard contacts need only be opened (or floated). Maximum Low State:.8V D V:.mA typical,.3ma max. 3V:.6mA typical, 8.6mA max. When Output urrent = ma Minimum High State Voltage: (+V supply -.6) V typical, (+V supply -4.) V worst case Maximum Low State Voltage: +.7V typical, +.V worse case When Output urrent = ma Minimum High State Voltage (+V supply -.4) V typical, (+V supply,.8) V worst case Maximum Low State Voltage: +.V typical, +.4V worst case ma Duty ycle of Pulses % Environmental onditions Operational Temperature Storage Temperature Relative Humidity Keying Wire Type and Range Wiring Arm Wiring Arm Screw Torque Type Range Restrictions ategory.6 microseconds o to 6 o (3 o to 4 o F) -4 o to 8 o (-4 o to 8 o F) to 9% (without condensation) Insert keying bands between: 8 and and and 4 Belden 877, 4ft maximum, use stranded copper wire only, wire per terminal ategory atalog Number 77-WN 9 pound-inches (.Nm) Publication 77-UMA EN P May

128 A Specifications Agency ertification (when product is marked) SA certified SA lass, Division, Groups A, B, and D certified UL listed E marked for all applicable directives -Tick marked for all applicable acts You use this conductor category information for planning conductor routing as described in publication 77-4., Industrial Automation wiring and Grounding Guidelines. Stepper ontroller Module Specifications (cat. no. 77-M) Module Location Backplane Power Requirement Maximum Number of Axes Keying Environmental onditions Operational Temperature Storage Temperature Relative Humidity Agency ertification (when product is marked) Bulletin 77 I/O Rack module slot.7a, V dc maximum Up to 3 Pulse Output Expander Modules (cat. no. 77-OJ) for control of up to 3 axes Insert keying bands between: and 4, and 8 and o to 6 o (3 o to 4 o F) -4 o to 8 o (-4 o to 8 o F) to 9% (without condensation) SA certified SA lass, Division, Groups A, B, and D certified UL listed E marked for all applicable directives -Tick marked for all applicable acts Publication 77-UMA EN P May

129 SA Hazardous Location Approval SA certifies products for general use as well as for use in hazardous locations. Actual SA certification is indicated by the product label as shown below, and not by statements in any user documentation. Example of the SA certification product label I Approbation d utilisation dans des emplacements dangereux par la SA La SA certifie les produits d utilisation générale aussi bien que ceux qui s utilisent dans des emplacements dangereux. La certification SA en vigueur est indiquée par l étiquette du produit et non par des affirmations dans la documentation à l usage des utilisateurs. Exemple d étiquette de certification d un produit par la SA I To comply with SA certification for use in hazardous locations, the following information becomes a part of the product literature for SA-certified Allen-Bradley industrial control products. This equipment is suitable for use in lass I, Division, Groups A, B,, D, or non-hazardous locations only. The products having the appropriate SA markings (that is, lass I Division, Groups A, B,, D), are certified for use in other equipment where the suitability of combination (that is, application or use) is determined by the SA or the local inspection office having jurisdiction. Important: Due to the modular nature of a PL control system, the product with the highest temperature rating determines the overall temperature code rating of a PL control system in a lass I, Division location. The temperature code rating is marked on the product label as shown. Temperature code rating I Look for temperature code rating here The following warnings apply to products having SA certification for use in hazardous locations. Pour satisfaire à la certification de la SA dans des endroits dangereux, les informations suivantes font partie intégrante de la documentation des produits industriels de contrôle Allen-Bradley certifiés par la SA. et équipement convient à l utilisation dans des emplacements de lasse, Division, Groupes A, B,, D, ou ne convient qu à l utilisation dans des endroits non dangereux. Les produits portant le marquage approprié de la SA (c est à dire, lasse, Division, Groupes A, B,, D) sont certifiés à l utilisation pour d autres équipements où la convenance de combinaison (application ou utilisation) est déterminée par la SA ou le bureau local d inspection qualifié. Important: Par suite de la nature modulaire du système de contrôle PL, le produit ayant le taux le plus élevé de température détermine le taux d ensemble du code de température du système de contrôle d un PL dans un emplacement de lasse, Division. Le taux du code de température est indiqué sur l étiquette du produit. Taux du code de température I Le taux du code de température est indiqué ici Les avertissements suivants s appliquent aux produits ayant la certification SA pour leur utilisation dans des emplacements dangereux.! WARNING: Explosion hazard Substitution of components may impair suitability for lass I, Division. Do not replace components unless power has been switched off or the area is known to be non-hazardous. Do not disconnect equipment unless power has been switched off or the area is known to be non-hazardous. Do not disconnect connectors unless power has been switched off or the area is known to be non-hazardous. Secure any user-supplied connectors that mate to external circuits on an Allen-Bradley product using screws, sliding latches, threaded connectors, or other means such that any connection can withstand a Newton (3.4 lb.) separating force applied for a minimum of one minute.! AVERTISSEMENT: Risque d explosion La substitution de composants peut rendre ce matériel inacceptable pour lesemplacements de lasse I, Division. ouper le courant ou s assurer quel emplacement est désigné non dangereux avant de remplacer lescomposants. Avant de débrancher l équipement, couper le courant ou s assurer que l emplacement est désigné non dangereux. Avant de débrancher les connecteurs, couper le courant ou s assurer que l emplacement est reconnu non dangereux. Attacher tous connecteurs fournis par l utilisateur et reliés aux circuits externes d un appareil Allen-Bradley à l aide de vis, loquets coulissants, connecteurs filetés ou autres moyens permettant aux connexions de résister à une force de séparation de newtons (3,4 lb. -, kg) appliquée pendant au moins une minute. SA logo is a registered trademark of the anadian Standards Association PL is a registered trademark of Allen-Bradley ompany, Inc. Le sigle SA est la marque déposée de l Association des Standards pour le anada. PL est une marque déposée de Allen-Bradley ompany, Inc. Publication 77-UMA EN P May

130 B SA Hazardous Location Approval Publication 77-UMA EN P May

131

132 Allen-Bradley, a Rockwell Automation Business, has been helping its customers improve productivity and quality for more than 9 years. We design, manufacture and support a broad range of automation products worldwide. They include logic processors, power and motion control devices, operator interfaces, sensors and a variety of software. Rockwell is one of the world s leading technology companies. Worldwide representation. Argentina Australia Austria Bahrain Belgium Brazil Bulgaria anada hile hina, PR olombia osta Rica roatia yprus zech Republic Denmark Ecuador Egypt El Salvador Finland France Germany Greece Guatemala Honduras Hong Kong Hungary Iceland India Indonesia Ireland Israel Italy Jamaica Japan Jordan Korea Kuwait Lebanon Malaysia Mexico Netherlands New Zealand Norway Pakistan Peru Philippines Poland Portugal Puerto Rico Qatar Romania Russia IS Saudi Arabia Singapore Slovakia Slovenia South Africa, Republic Spain Sweden Switzerland Taiwan Thailand Turkey United Arab Emirates United Kingdom United States Uruguay Venezuela Yugoslavia Allen-Bradley Headquarters, South Second Street, Milwaukee, WI 34 USA, Tel: () Fax: () Publication 77-UMA EN P May Supersedes Publication July 988 PN Publication 77-UMA EN P opyright Allen-Bradley ompany, May Inc. Printed in USA