General Specifications

Transcription

1 General Specifications and Server Communication Communication 1. General The protocol can be used for DCS communication for the and analyzer server. This communication protocol was first established for the Programmable Logic Controller (PLC) made by Gould, Inc., and is now used as the universal communication protocol between different systems. Here the specification of Modbus communication which is applied for and server is introduced. Regarding the general specification of Modbus, refer to Modbus Protocol Reference Guide. 1.1 Configuration was started as a method to allow a master device to control multiple slave devices. device with a device number is connected to a master. Master (DCS) 2. Specifications 2.1 Communication Transmission Modes There are two modes for signal transmission between the master and slave; RTU (Remote Terminal Unit) mode and ASCII mode. The analyzer server supports the RTU mode only, however, the analyzer supports both modes. Item Number of data bits Message starting character Message ending character ASCII mode RTU mode 7 bits (ASCII) 8 bits (binary) Colon : Carriage return/line <cr><lf> feed None Message length 2N+ 1 N interval of data Error detection None 1 second or shorter 24 bit-time or shorter LRC (logical redundancy check) CRC-16 (cyclic redundancy check) T01.EPS Slave 1 Slave 2 Slave 3 Slave 4 Figure 1.1 configuration F1_1.EPS The master device (master) can send a query (i.e. poll) or command to a slave device (slave) on a regular basis or when required. In either case, the master starts signal transmission then the slave responds. Master Command message Response message Slave F1_2.EPS Figure 1.2 Master-slave command and response cycle A message transmitted between devices contains the device number, function, data, and error check code. The function is encoded depending on the message characteristics and data type. The error check code checks the validity of the entire message. 2.2 Message Configuration A message consists of four fields: device number, function, data, and error check. It is always sent in this sequence. In ASCII mode, a colon : is the starting character and carriage return/line feed <cr><lf> is the message ending string. The portion between the starting character and ending string is the message body. The communication message is entirely ASCII codes. The message excluding the starting character and ending string consists of 0 to 9 and A to F representing hexadecimal numbers. In RTU mode, the message consists of binary codes and can be transmitted faster than in ASCII mode. If the signal interval is more than 24 bit-time in the transmission line, the start of a new message is identified. In this system, time-out is 10 ms regardless of the transmission speed. Figure 2.3 Message configuration F2_3.EPS (1) The device number is set in advance for each slave and ranges from 1 to 254. This number is same as ID. The ranges from 1 to 240 is assigned as, 241 to 254 as server. The master performs signal transmission to each slave simultaneously. slave checks the device number in the message to determine whether the received Yokogawa Electric Corporation , Nakacho, Musashino-shi, Tokyo, 180 Japan Tel.: Fax.: Copyright Jan. 1998(YG) 1st Edition Jan. 1998(YG)

2 message is directed to the slave itself and returns a response message. For some functions, 0 can be specified as the device number. In this case, all slaves execute the receiving process of the same command message at the same time. However, the response message is not sent back. 0 is supported by the analyzer server only. For the analyzer, device number 0 results in a device number error. (2) s The master specifies the function to be executed by the slave. The analyzer or analyzer server supports the following functions in the protocol. write, and loop function, the same message as the command message is sent back. For the read function, the device number plus function added with the read data are sent back as the response message. If an address to which data is not allocated is read, an error is not generated but zero (0) is responded as the read data. (2) Error response If the command message is faulty, the slave does not execute the command but sends back an error response. The master can check whether the command is accepted successfully by checking the function in the response message. If an error is identified, the details can be checked from the error code. 2 No. 01 Coil status read 02 relay status read Holding content read content read Single coil change status Single holding write 08 Loopback test Reads the ON/OFF series of coils. status of a Reads the ON/OFF status series of input relays. of a Reads the current value of a series of ho lding s. Reads the current value of a series of input s. Forcibly changes the status of a coil. Writes a value to a holding. Sends back the same message as the command message. T02.EPS Error function (command function + 128) Error code Error code 1 2 Figure 2.4 Response to a faulty command message 0 code error (non-existent function) F2_4.EPS 0 C oil, input relay, or number error (more than 8000) 03 Number of coils, input relays, or s error (s: more than 125, coils/input relays:more than 2000) 04 An unrecoverable error occurred on the slave while the command message was being executed. 11 Set data error (out of range) (3) There are two types of data coil/relay in bits and as 16-bit data. The coil uses two values (ON/OFF or 0/1), while the ranges from 0 to Up to 8000 coils/ relays or s can be accessed and 1 to 8000 addresses are assigned. Device Contact R/W R R/W R name Device number Coil relay Holding resistor XXXX : 0001 to 8000 Application number 0XXXX Command 1XXXX Status 4XXXX Set value 3XXXX Measured value T03.EPS (4) A message is followed by an error check code to detect a message error (i.e. bit changes) caused by signal transmission. In ASCII mode, an error check code according to LRC (logical redundancy check) is used. In RTU mode, an error check code according to CRC-16 (cyclic redundancy check) is used. 2.3 Slave Response When the slave receives a command from the master, it performs an error check then sends back a normal response if the command is normal, or an error response if the command is abnormal. (1) Normal response For the single coil status change, single holding T04.EPS (3) No response In the following cases, the slave ignores the command message and does not send back a response (no response). If the device number is 0 (broadcasting), all slaves execute the command but do not send back a response. 1. When a transmission error (overrun, framing error, parity error, or CRC error) is detected in the command message 2. When the device number in the command message does not match the slave number assigned to the slave 3. Communication Specifications For communication, the DCS communication port of the or analyzer server is used. The analyzer has a DCS communication port, while the analyzer server has up to three DCS communication ports. Communication standard: RS-422 ( output)/rs-232c (output) Start-stop synchronization: Start bit 1, data bit 7/8, parity bit 1, stop bit 1 Communication speed: 1200, 2400, 4800, 9600 bps (selectable) Error detection: Odd number parity, even number parity, none (selectable) Transmission mode: ASCII mode ()/RTU mode All Rights Reserved. Copyright 1998, Yokogawa Electric Corporation 1st Edition Jan.05,

3 4. System Configuration (1) For the communication port, an RS-422 standard serial port is used. This standard is converted into the RS-232C standard via a communication converter (K9404LD) then connected to the DCS. This communication converter has a protection feature that automatically disconnects communication if the explosion-proof feature of the cannot be maintained. analyzer Field RS422 Panel/office Communication converter K9404LD Note RS232C Power off signal DCS Note : Dedicated communication line (RS-422) 0.75 mm 2 twisted pair x 3, cable outside diameter 10 to 15.9 mm, up to 1 km (*) Flameproof packing cable must be constructed on the analyzer side. Refer to " Installation Manual (TI 11B3A103E)." * Parts, cables, and construction materials must be prepared by the customer. F4_1.EPS Figure 4.1 (2) Server server HUB RS232C HUB HUB Note DCS Control room Field Note : Analyze Server is connected to DCS with the cable of RS232C D-sub 25 pin straight. F4_2.EPS Figure 4.2 server 5. Communication 5.1 Coil (command contact) (1) Run command Commands the start of continuous analysis to the. (2) Stop command Commands the stop of continuous analysis to the. (3) Requests the to set the system clock. (4) Change to main pattern request Requests of changing the appointed operational pattern as the main pattern. (5) Interrupt pattern execution request Requests of changing the appointed operational pattern as an interrupt pattern. Note 1: Coil reset the status from 1 to 0 automatically when the message is accepted by. Note 2: The command regarding the operation executes after the analysis finished. Note 3: It is needed to use the input relay if the command is accepted or not Relay (status contact) (1) normal The is normal. If there is no alarm of alarm level 1 (critical failure) or level 2 (minor failure), 1 is displayed. (2) failure The is faulty. If there is at least one alarm of alarm level 1 (critical failure), 1 is displayed. (3) server failure The analyzer server is faulty. If there is at least one alarm of alarm level 1 (critical failure), 1 is displayed. (4) Alarm status change The alarm status to the is changed. After a new alarm occurs, when the alarm status change is read, 1 is read. Then, when at least one alarm status is read, the status is reset to 0. (5) Measuring (run mode) The is measuring. In RUN mode, 1 is displayed. Otherwise, 0 is displayed. (6) Stop (ready mode) The stops. In READY mode, 1 is displayed. Otherwise, 0 is displayed. (7) Maintenance (other modes) If the is in MANUAL, LAB, or PAUSE mode, 1 is displayed. Otherwise, 0 is displayed. (8) Executing the operational pattern The corresponding pattern is being executed. (9) update New data can be acquired for each task. After new data arises, when data update is read, 1 is read. Then, at least one analysis value is read, and the status is reset to 0. All Rights Reserved. Copyright 1998, Yokogawa Electric Corporation 1st Edition Jan.05,

4 (10) valid is valid for each analysis value. The requirements for validity are that the analysis value is between the upper and lower limits, the retention time is at or below the upper limit, and for operation data, the data to be used for operation is valid. (11) Alarm status The alarm status of the and analyzer server is displayed for each alarm number. If an alarm occurs, 1 is displayed. Otherwise, 0 is displayed. The alarm number is 1 to 99 for level 1 alarms of the analyzer, 101 to 199 for level 2 alarms, and 201 to 249 of analyzer server alarms. The analyzer bus regular cycle communication off alarm is assigned to 249. (12) Calibration factor update Whether a new calibration factor is updated is displayed for each task. After the calibration factor is updated, when calibration factor update is read, 1 is read. Then, if at least one calibration factor is read, the status is reset to Holding Register (set data) (1) setting value This is a set of four s used by the DCS to set the analyzer clock. When the time is made, this setting value is set in the analyzer system clock. These s are also used for the coil time setting request. When Server is set the time and date all connected to Server is set the same time and date. Example: September 25, 1996, 15:23:10 Month Minute Year Hour Day Second * 1 07CC (Hexadecimal) 0919 (Hexadecimal) 000F (Hexadecimal) 170A (Hexadecimal) Figure 5.1 configuration F5_1.EPS (2) change The DCS sets the starting task number of a operational pattern on the. If the objected operational pattern set a single task, continuous measurement can be performed by specifying the flow path. (3) Analysis value Same data as the analysis value in the input can be read but cannot be written. 5.4 Register (measured data) (1) number The currently selected task number is displayed. In stop or MANUAL mode, the task number is 0. In LAB mode, the task number is (2) Starting peak number The starting peak number assigned to each task is displayed. The number of analysis values is 255 or fewer (including the peaks of all tasks). The number is 0 if no peak is assigned. (3) Peak number Peak number assigned to each task is displayed. See the figure below. Example: The peak number of 2, Peak 3 is 7 Starting peak number = 1 Starting peak number = 5 Starting peak number = 15 Starting peak number = Figure 5.2 Example of peak allocation Number of peaks = 4 Number of peaks = 10 Number of peaks = 10 F5_2.EPS (4) Sampling time This contains the sampling time for each task. Hour and minute are stored. Example: 15: 23 Hour Minute 0F17 (Hexadecimal) F5_3.EPS (5) Analysis value This contains each analysis value. The value is represented by a fraction to the full scale or by a real number (floating point format). The full scale is set in advance for each analysis value. As the scaling factor, either 9999 or can be selected. The real number format conforms to the IEEE standard and requires two s per data. Fraction format: (Analysis value * Scaling factor)/full scale value For example, the analysis result is 5 ppm (0-20 ppm range), in this case, reading value to use scaling factor 9999 is = 2499 (09C3) F5_4.EPS For the real number format, units (such as %, ppm, etc.) are considered. For example, the floating point value converted from 1.5 can be read for 1.5 %. (6) Retention time This contains the retention time for each analysis value. The unit is in seconds. (7) Calibration factor This contains the calibration factor for each analysis value to are multiplied by 1000 and displayed (i.e to 9999). All Rights Reserved. Copyright 1998, Yokogawa Electric Corporation 1st Edition Jan.05,

5 6. ing 6.1 General Rules In this system, the process control system is positioned as the master device, and the or analyzer server as the slave device. The ID number corresponds to the device number. However, since the analyzer server controls multiple s, an analyzer server has multiple device numbers corresponding to these s. The operation command is assigned to the coil, the status flag to the input relay. The set value corresponds to the holding, and the measured value such as the analysis result to the input. Up to 8000 coils/relays or s are available. es 1 to 8000 are assigned for access from the master. The data is for each analyzer, each operational pattern, each task, or for each peak. The relationship between the data and address is defined as shown below Mapping Feature The analyzer server has 512 s that can be set by the user for each of the Coil, relay, Holding, and. The device number and address of the connected can be set in the. The address ranges from X7001 to X7512. With the device feature, data required by the DCS can be selected from the data prepared by the at a time and can be transferred to the DCS continuously. DCS X7001 X7002 X7003 Mapping analyzer operational pattern task peak 000X X: Item number (1 to 9) Application 00XP X: Item number (1 to 9), P: Pattern number (1 to 4) 0 XTT X: Item number (1 to 9), TT: number (1 to 32) XCCC X: Item number (1 to 255) (1 to 6), CCC: peak number T05.EPS X7512 Figure 6.1 Mapping feature F6_1.EPS 6.2 Exceptions server normal/error of the relay shows the analyzer server status. Therefore, the same information is displayed for all device numbers connected to an analyzer server. The alarm status of the relay is displayed as 1 or 0 by checking the alarm status against the address and alarm number. In this case, the alarm status is not for each peak but addresses to are used. (The number from the place of 100 is the alarm number.) For the analysis value of the, either the fraction format or real number format can be selected. In the real number format, two s are required per data, so the address is twice as large as the peak number. For example, addresses of data #1, #2, and #3 in the real number format are , , and All Rights Reserved. Copyright 1998, Yokogawa Electric Corporation 1st Edition Jan.05,

6 6 7. Table 7.1 Table (general) Coil relay Holding Name Run command Stop command Change to main pattern request Interrupt pattern command normal error execution status change Measuring Stop Maintenance server normal server error Executing pattern update Calibration factor update valid Alarm status change Analysis value number Starting peak number Number of peaks Sampling time Analysis value Retention time Calibration factor Unit Pattern When the message is received, the slave is reset P 0002P 1001P 101TT 102TT 11CCC Reset when the change is read. alarm status is read after alarm status Reset when the analysis value is read after data update is read. Reset when the calibration factor update is read. 12AAA AAA: Alarm number (1 to 245) Component P Year (40001), month/day minute/second (40004) 41DDD Read only. Write disabled. 301TT Peak starting position for each task 302TT Number of peaks for each task 303TT Hour/minute 31CCC/- 31DDD 32CCC Second Analysis value (CCC: the real number factor is read after calibration (40002), hour (40003), 33CCC Analysis value (CCC: Peak number) Peak number), DDD=CCC*2-1 for T06.EPS All Rights Reserved. Copyright 1998, Yokogawa Electric Corporation 1st Edition Jan.05,

7 7 7.2 Table ( ) Name Unit Pattern Peak When the message is received, the slave is reset. Coil 07XXX XXX: 001 to 512 server normal server error Alarm status change Reset when the change is read. alarm status is read after alarm status Relay Alarm status 101AA AA: Alarm number (1 to 49) 17XXX XXX: 001 to Year (40001), month/day minute/second (40004) (40002), hour (40003), Holding Register 47XXX XXX: 001 to 512 Register 37XXX XXX: 001 to 512 T07.EPS All Rights Reserved. Copyright 1998, Yokogawa Electric Corporation 1st Edition Jan.05,