Applications & Tools. Safety position, standstill and direction detection and monitoring safely limited speed (SLS) on the basis of Distributed Safety

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1 Safety position, standstill and direction detection and monitoring safely limited speed (SLS) on the basis of Distributed Safety Distributed Safety Application Description July 2013 Applications & Tools Answers for industry.

2 Siemens Industry Online Support This article is taken from the Siemens Industry Online Support. The following link takes you directly to the download page of this document. 2 V 1.0a, Entry ID:

3 s Task 1 Solution 2 Program Structure 3 SIMATIC Application of an F Position Encoder F Position Encoder 4 Realizing the Functionalities 5 Required Components 6 Installation 7 Operating the Application 8 Norm Considerations 9 History 10 V 1.0a, Entry ID:

4 Warranty and Liability Warranty and Liability Note The application examples are not binding and do not claim to be complete regarding configuration, equipment and any eventuality. The application examples do not represent customer-specific solutions. They are only intended to provide support for typical applications. You are responsible for ensuring that the described products are used correctly. These application examples do not relieve you of the responsibility to use sound practices in application, installation, operation and maintenance. When using these Application Examples, you recognize that we cannot be made liable for any damage/claims beyond the liability clause described. We reserve the right to make changes to these application examples at any time without prior notice. If there are any deviations between the recommendations provided in this application example and other Siemens publications e.g. Catalogs the contents of the other documents have priority. We accept no liability for information contained in this document. Any claims against us - based on whatever legal reason - resulting from the use of the examples, information, programs, engineering and performance data etc., described in this application example shall be excluded. Such an exclusion shall not apply in the case of mandatory liability, e.g. under the German Product Liability Act ( Produkthaftungsgesetz ), in case of intent, gross negligence, or injury of life, body or health, guarantee for the quality of a product, fraudulent concealment of a deficiency or breach of a condition which goes to the root of the contract ( wesentliche Vertragspflichten ). However, claims arising from a breach of a condition which goes to the root of the contract shall be limited to the foreseeable damage which is intrinsic to the contract, unless caused by intent or gross negligence or based on mandatory liability for injury of life, body or health. The above provisions do not imply a change in the burden of proof to your detriment. It is not permissible to transfer or copy these Application Examples or excerpts thereof without express authorization from Siemens Industry Sector. Before using this application example, please read the warning note in chapter 8 Operating the Application. WARNING 4 V 1.0a, Entry ID:

5 Table of Contents Table of Contents Warranty and Liability Task Solution Program Structure F Position Encoder Realizing the Functionalities Safe standstill detection Safely limited speed (SLS) Safe position detection Block description Modulo consideration Safe direction detection Required Components Installation Operating the Application Norm Considerations History V 1.0a, Entry ID:

6 1 Task 1 Task Introduction For a multitude of industrial application the precise recording of a position is pivotal. However, detecting a position is always accompanied by a motion of, for example, cranes, robots or general machine parts. In many cases this can cause dangerous situations. Nevertheless, hazards can also occur if a desired position is not reached or a prohibited position is reached. To avoid these hazards, these position values have to be safe. This is also the case for position detection and for the subsequent position processing. This leads to the question how position detection can be realized whilst keeping safety in mind. 2 Solution Options of safe position detection For the safe detection of a position, SIEMENS drives with integrated safety functions (for example, SINAMICS G120) offer various applications. Another option is the use of safe position encoders (below, further referred to as F position encoders). In combination with a SIMATIC F-CPU, these securely detected values can be processed further and corresponding responses can be arranged. This safety functional example describes the use of such an encoder. Figure to automation solution DP Master F-CPU DP Slave F Position encoder DP F-CPU and F position encoders communicate through the PROFIBUS DP with each other. The safety-relevant data is exchanged through the PROFIsafe bus profile, via the same bus line as the standard data. 6 V 1.0a, Entry ID:

7 2 Solution What are the contents of this function example? The function example shows you how you can easily integrate an F position encoder on the PROFIBUS. As a result, you can realize a number of safetyrelevant issues with the F-CPU. In this example, the following issues are introduced: Safe standstill detection Monitoring safely limited speed (SLS) Safe position detection Safe direction detection These issues can be realized, since many F position encoders on the market can output safe speed and also a safe position. Each of theses four issues is realized in the included STEP 7 project within a separate block (F-FB). This modularity permits you to integrate individual blocks that have been prepared here to your individual STEP 7project and to adjust them to your automation task. The emphasis of this function example is the fast integration of an F encoder (through PROFIBUS) into a STEP 7 project with prepared F blocks. The function example has therefore a universal character. Although error states are detected by the prepared F blocks, error handling is not the emphasis of this function example, this is to say, the error states displayed on the F blocks have to be processed further by you, for example, to safely switch off of the actuators. What are the advantages of this function example? The document on hand, offers you the following advantages: Simple integration of third party products (F position encoder) to a SIMATIC F- CPU Possible solution as possible alternative for a less complex system such as, for example, SINAMICS The safety relevant data is transferred through the already existing standard bus. This enables great savings on the installation and engineering. V 1.0a, Entry ID:

8 3 Program Structure 3 Program Structure Screenshot Standard User Program F Program OB1 FC 1 F-CALL F-PB (FB 1) MAIN FB15 SSTILL Save standstill detection OB35 FB16 SLS Monitoring safely limited speed (SLS) FB17 F_POSITION Save position detection Description Reintegration FB18 DIR Save direction detection Each of the above mentioned functionalities is realized modularly in a separate and failsafe FB (FB 15-FB 18). These function blocks are called by the F program block FB F_MAIN (FB 1). In FB F_MAIN (FB 1) a reintegration of the encoder is also prepared. The reintegration is realized through the ACK variable. Note An acknowledgement after an error or a reintegration after a passivation is realized (positive edge) through one and the same signal (ACK). Note After the first switch on, the F position encoder may be in passivation (no exchange of process data). Reintegrate the F position encoder with ACK=1. A standard user program is not prepared. Only the interrupt alarm OB (OB 35) calls the F runtime group (F-CALL) as usual. 8 V 1.0a, Entry ID:

9 4 F Position Encoder 4 F Position Encoder General properties For this function example, an absolute value encoder with DP interface is used. The encoder manufacturer has to provide the device master data file (GSD) for the connection to PROFIBUS. Generally, incremental encoders can also be used. However, in this case, to detect the position, the encoder has to be referenced to the appropriate position after it was switched on. Since the encoder is to be used for safety-relevant applications, it has to be certified according to IEC 62061, ISO and/or IEC The safety-related data of the F position encoder that is to be evaluated by the F- CPU can have a maximum length of 16 bits. Encoders used in the STEP 7 project An F position encoder (subsequently TR encoder ) by TR Electronic is inserted in the included STEP 7 project. In the F program, the following information of the F position encoder is safely evaluated: Position Speed The position is represented by Number of revolutions angle Number of revolutions (multi turn) For each whole revolution, the position value is counted up by 1 or counted down by 1 for a whole revolution in counter direction. A value range from 0 to a maximum of is covered. After the count jumps to 0 after another positive revolution; negative values are not output, irrespective or the direction of rotation. The value range is processed in the F program in the INTEGER data format. This value range can be divided into more detail by the angle. Angle (single turn) With each rotation, a range from 0 to 360 degrees is covered. Thus, the value for the number of revolutions is divided again. The value range of a revolution from 0 to 360 degrees is illustrated by the encoder through a numerical value of 0 to 8191; negative values are not output, irrespective of the direction of rotation. The value range is processed in the F program, in the INTEGER data format. Safely limited speed value The permitted value range comprises values from to and therefore considers the sign. If the permitted value range is exceeded, this is safely detected by setting a bit. The value range is processed in the F program, in the INTEGER data format. V 1.0a, Entry ID:

10 4 F Position Encoder Assigning the address between F-CPU and TR encoder After the integration of the TR encoder in HW Config the (modifiable) address range is specified. The address assignment is shown in the figure below. Details Encoder Manufacturer Address Assignment in HW Config Byte X+0 X+1 X+2 X+3 X+4 X+5 X+6 X+7 X+8 X+9 X+10 X+11 X+12 X+13 Bit Input Data Cam data TR Status Speed Actual value (multi turn) Actual value (single turn) Safe Status CRC2 Data Type WORD WORD INTEGER INTEGER INTEGER BYTE 3 BYTES In this example, the addresses start with 7 (see E address in HW Config). The following applies for the table details encoder manufacturer : X=7 If you want to, for example, read out the speed safely, load the address EW 11 (due to X+4=11) in the F program. As shown by the details of the manufacturer in the figure, the following input data is processed in this STEP 7 project: Speed Actual value of the number of whole revolutions (multi turn) Actual value of the angle (single turn) The TR encoder supplies a safe bit, which is set at inadmissibly high speed. This bit (OV_VELO) is also processed in the F program. The encoder values are accessed through the process image of the inputs (PII). 10 V 1.0a, Entry ID:

11 5 Realizing the Functionalities 5 Realizing the Functionalities What will you find here? This chapter explains the four realizable functionalities of the function example in more detail: Safe standstill detection (chap. 5.1) Safely limited speed (SLS) (chap. 5.2) Safe position detection (chap. 5.3) Safe direction detection (chap. 5.4) Acknowledgement and reintegration For the acknowledgement after an error, the same signal (ACK) is used as for the reintegration after passivation. 5.1 Safe standstill detection What can the block perform? Safe standstill detection is used, for example, to release a protective door only after the standstill of a dangerous machine. The block provides the information that the drive connected to the F position encoder has safely stopped. For this purpose, the current speed, provided safely by the encoder, is compared with zero (standstill). Since the encoder in standstill can still output various values in zero (for example, due to the noise of the analog inputs), you can determine a tolerance value whose range still defines a standstill. The block detects an error (ERR_STILL=1), if after requesting the safe standstill and after a tolerance time has lapsed, the value of the current speed is above the tolerance value defined by the standstill. The error responses, such as, for example, safe switch off of the actuators, are to be performed by the user. Parameter description of the FB SSTILL (FB 15) FB SSTILL (FB 15) Input parameters Data type Description VELO_ACT INTEGER Current speed of the encoder. VELO_TOL INTEGER Tolerance value (standstill defining value range) OV_VELO BOOL 1: speed value outside of the permitted value range Automatically set by the encoder. REQ_SSTILL BOOL 1: request safe standstill T_TOL TIME Time starts at REQ_SSTILL=1. Once time has lapsed, it has to be VELO_ACT < VELO_TOL (applies for the values), otherwise the ERR_SSTILL error bit is set. ACK BOOL 1: error acknowledgement or reintegration Output parameters Data type Description SSTILL BOOL 1: safe standstill reached ERR_SSTILL BOOL Error bit, 1: error V 1.0a, Entry ID:

12 5 Realizing the Functionalities Description of realizing the FB SSTILL (FB 15) The current safe speed of the encoder VELO_ACT is signed. The VELO_TOL tolerance value, defining the standstill can also be specified signed. However, for the error detection only the values of VELO_ACT and VELO_TOL are relevant. If a safe standstill (REQ_SSTILL = 1) is requested, the T_TOL tolerance time starts to expire. After the expiry of T_TOL the following has to apply: IVELO_ACTI IVELO_TOLI. Note Q is set if REQ_SSTILL = 1 and the T_TOL time has lapsed. FB F_TON is a block from the Distributed Safety library. If you use the FB SSTILL (FB 15) in a separate STEP 7 project, you also have to insert the FB F_TON in your separate STEP 7 project (SIMATIC Manager). 12 V 1.0a, Entry ID:

13 5 Realizing the Functionalities The standstill and error detection in network 6 forms the core of the FB SSTILL (FB 15): Each of the first two comparators (CMP) on the four AND blocks evaluate the sign of the current speed (VELO_ACT) and the tolerance value (VELO_TOL). Each of the third comparator on the four AND blocks compares (depending on the sign) VELO_ACT with VELO_TOL. If the condition on all AND blocks is not fulfilled, there is definite standstill (SSTILL=1). If the condition is fulfilled on one AND block and the tolerance time (Q=1) has lapsed, then the error bit (ERR_SSTILL=1) is set. The error can be acknowledged with ACK=1. OV_VELO Overflow bit from encoder OV1..Check overflow after arithmetic operation (network 3) OV2..Check overflow after arithmetic operation (network 5) Variables with the 2K ending name the two s complement. This is required for the sign evaluation of VELO_ACT and VELO_TOL. Explanation to VELO_ACT_2K and VELO_TOL_2K Since VELO_ACT is signed and VELO_TOL can also be specified with negative signs, there can be different combinations (for example, VELO_ACT>0 and VELO_TOL<0) between the two variables regarding the sign. To consider negative signs, the two s complement was formed for VELO_ACT and VELO_TOL, and stored in the VELO_ACT_2K and VELO_TOL_2K variable. This makes it possible to perform the comparative operations (see CMP block in the above figure) in a way that eventually, the values of VELO_ACT and VELO_TOL are compared with each other. V 1.0a, Entry ID:

14 5 Realizing the Functionalities 5.2 Safely limited speed (SLS) What can the block perform? Safely limited speed (SLS): is used, for example, to permit access to normally dangerous areas, for example, for maintenance work. With FB SLS (FB 16) you can request safe monitoring of limited speed (SLS) (through REQ_SLS). The value of the current speed that is provided safely by the encoder has to be smaller than the configured safely limited speed (SLS_SETPOINT) after the expiry of the configured tolerance time T_TOL. If this is not the case, this is detected as an error. Subsequent error responses, such as, for example, safe switch off of the actuators has to be performed by the user. Parameter description FB SLS (FB 16) Input parameters Data type Description REQ_SLS BOOL 1: SLS request VELO_ACT INTEGER Current safe speed of the encoder. SLS_SETPOINT INTEGER Limit value for SLS T_TOL TIME Time starts at REQ_SLS=1. Once the time has lapsed, it has to be IVELO_ACTI < ISLS_SETPOINTI, otherwise the ERR_SLS error bit is set. OV_VELO BOOL 1: speed value outside of the permitted value range Set automatically by the encoder. ACK BOOL 1: error acknowledgement or reintegration Output parameters Data type Description ERR_SLS BOOL Error bit 1: error SLS BOOL 1: Condition IVELO_ACTI < ISLS_SETPOINTI is complied with at REQ_SLS=1 and no error is pending. 14 V 1.0a, Entry ID:

15 5 Realizing the Functionalities Description of the realization The current safe speed of the encoder VELO_ACT is signed. The SLS_SETPOINT setpoint that must not be exceeded to achieve safe speed can also specified signed. However, for the error detection only the values of VELO_ACT and SLS_SETPOINT are relevant. If a safe speed (REQ_SLS = 1) is requested, the T_TOL tolerance time starts to expire. After the expiry of T_TOL the following has to apply: IVELO_ACTI ISLS_SETPOINTI. Note Q is set if REQ_SLS = 1 and the T_TOL time has lapsed. FB F_TON is a block from the Distributed Safety library. If you use the FB SLS (FB 16) in a separate STEP 7 project, you also have to insert FB F_TON in your separate STEP 7 project (SIMATIC Manager). V 1.0a, Entry ID:

16 5 Realizing the Functionalities The core of the block is monitoring whether after requesting (REQ_SLS=1) and after the expiry of the T_TOL tolerance time, the VELO_ACT current speed is below the configured SLS_SETPOINT limit value. Each of the first two comparators (CMP) on the four AND blocks evaluate the sign of the current speed (VELO_ACT) and the tolerance value (VELO_TOL) for the safely limited speed SLS_SETPOINT. The third comparator each on the four AND blocks compares (depending on the sign) VELO_ACT with SLS_SETPOINT. If the condition is fulfilled on one AND block and the tolerance time (Q=1) has lapsed, then the error bit (ERR_SLS=1) is set. The error can be acknowledged with ACK=1. OV_VELO Overflow bit from encoder OV1..Check overflow after arithmetic operation (network 3) OV2..Check overflow after arithmetic operation (network 5) 16 V 1.0a, Entry ID:

17 5 Realizing the Functionalities 5.3 Safe position detection Introduction Apart from the functionality of the block (chap ), this chapter deals with the modulo issue (chap ) separately Block description What can the block perform? You can define a start and an end position as danger range on this block. If the current position is within the danger range, this is safely detected. Start position End position Danger range Position value The start and end position is each clearly determined through the number of whole revolutions (multi turn) and angles (single turn): POS_SAFE_MULTI_BEGIN Start position Danger range End position Position value POS_SAFE_SINGLE_BEGIN POS_SAFE_MULTI_END POS_SAFE_SINGLE_END The appropriate FB F_POSITION (FB 17) block also includes standstill detection. This is not required for the actual position detection, however, this is dealt with when discussing the modulo issue. V 1.0a, Entry ID:

18 5 Realizing the Functionalities Parameter description FB F_POSITION (FB 17) Input parameters Data type Description POS_MULTI_ACT INTEGER Current position, specified by the number of whole revolutions of the encoder. This value is signed. POS_SINGLE_ACT INTEGER The current position, specified by the number of whole revolutions of the encoder is supplemented by this angle value (POS_SINGLE_ACT), which outputs a 360 area (part revolution) as numerical value. POS_SAFE_MULTI_ BEGIN INTEGER The Start of the danger range is clearly (and safely) defined by two numerical values: number of whole revolutions part revolution (0 to < 360 ) POS_SAFE_SINGLE _BEGIN POS_SAFE_MULTI_ END INTEGER INTEGER This input parameter specifies the number of whole revolutions. This value is signed and the following has to apply: POS_SAFE_MULTI_BEGIN < POS_SAFE_MULTI_END The Start of the danger range is clearly (and safely) defined by two numerical values: number of whole revolutions part revolution (0 to < 360 ) This input parameter specifies the part revolution (0 to < 360 ). The End of the danger range is clearly (and safely) defined by two numerical values: number of whole revolutions part revolution (0 to < 360 ) This input parameter specifies the number of whole revolutions. This value is signed and the following has to apply: POS_SAFE_MULTI_BEGIN < POS_SAFE_MULTI_END The End of the danger range is clearly (and safely) defined by two numerical values: number of whole revolutions part revolution (0 to < 360 ) POS_SAFE_SINGLE _END INTEGER This input parameter specifies the part revolution (0 to < 360 ). 18 V 1.0a, Entry ID:

19 5 Realizing the Functionalities FB F_POSITION (FB 17) Input parameters Data type Description VELO_ACT INTEGER Current safe speed of the encoder to detect standstill. This in turn, is used for the modulo consideration. VELO_TOL INTEGER Tolerance value (standstill defining value range) to detect the standstill. This in turn, is used for the modulo consideration. OV_VELO BOOL 1: speed value outside of the permitted value range Automatically set by the encoder. ACK BOOL 1: error acknowledgement or reintegration Output parameters Data type Description DANGER_RANGE BOOL 1: Object in danger range ERR_MODULO BOOL 1: modulo error (see chap ) ERR_VELO BOOL 1: Error during speed monitoring Description of the realization It is compared whether the current position is in the danger range (DANGER_RANGE=1) or not (DANGER_RANGE=0). This information (DANGER_RANGE=1) does not yet contain a safety-relevant action (such as, for example, stopping the actuators). This has to be performed by the user. V 1.0a, Entry ID:

20 5 Realizing the Functionalities Modulo consideration What does it involve? The entire area covered by the F position encoder starts at zero: POS_SAFE_MULTI_BEGIN = 0 POS_SAFE_SINGLE_BEGIN = 0 The entire area covered by the F position encoder stops at: POS_SAFE_MULTI_END = POS_SAFE_SINGLE_END = 8191 POS_SAFE_MULTI_BEGIN = 0 POS_SAFE_SINGLE_BEGIN = 0 POS_SAFE_MULTI_END = POS_SAFE_SINGLE_END = 8191 Value range of F position encoder Position value Ensure that the position detection only takes place in this defined range so that a counter overflow (modulo jump) does not occur. For application where the defined value range of the F position encoder is not sufficient, the modulo jump (transfer from the maximum count to 0 and the other way around) has to be taken into account. Detecting the modulo jump is important because the position detection in the F program is mainly based on mathematical comparison (>, <, =). When comparing the count (>, <, =), a variation of the count (for the current position), for example, between 0 and 32767, may lead to a result that does not correspond to the reality and may cause undesired responses. The F_POSITION (FB 17) block of the included STEP 7 project, detects this modulo jump. In the following, it is described how the FB F_POSITION (FB 17) block performs this. Explanations to the modulo jump If a modulo jump occurs, then the ERR_MODULO output variable is set in the FB F_POSITION (FB 17). Responses to a modulo jump are to be performed individually by the user. The modulo jump is detected by comparing the current actual position value with the actual position value of the previous program cycle (whilst taking into account the direction of count). This is illustrated below. Note All of the following considerations assume a forward counting direction. The thus resulting statements can also be performed for a backward counting direction. 20 V 1.0a, Entry ID:

21 5 Realizing the Functionalities For a forward counting direction, the following has to apply: Current position value > previous position value The figure below fulfills this requirement. Count (position value) max Modulo jump 0 Current position value Previous position value t t If a modulo jump (at forward counting direction) occurs now, the following applies: Current position value > previous position value no longer: t Count (position value) Current position value Previous position value t t t This Modulo jump is detected by FB F_POSITION (FB 17) by setting the ERR_MODULO output variable. The following scenarios are not recorded by the FB F_POSITION (FB 17): The speed of rotation is so large, that a modulo jump takes place and the following applies: Current position value > previous position value (at forward counting direction). Count (position value) Previous position value Current position value t t t V 1.0a, Entry ID:

22 5 Realizing the Functionalities How is the modulo jump detected? This is how the modulo jump is detected in the F program: Saving the current actual position value for the next program cycle Standstill detection Modulo evaluation Below, these three points are explained. Saving the current actual position value for the next program cycle The aim of networks 1 to 5 consists of the first saving of the position value to be able to access it in the next program cycle. NW Screenshot Explanation 1 The HELP_VAR help variable ensures that NW1-5 is only run once to save the current position value for the next program cycle. 2 With POS_MULTI_M the current position value for the next program cycle is saved. 3 If the F position encoder is ready to operate (QBAD=0) so that the current POS_MULTI_ACT (in NW2) position was saved, HELP_VAR is set so that NW2-4 are no longer run through. 4 As long as HELP_VAR has not been set, the block is left at this point. 5 To jump NW2-4 at HELP_VAR=1. After the first saving of the current position value for the next program cycle, networks 2 to 4 are no longer run through. Saving the current position value for the next program cycle is performed at the end of the block: Standstill detection The standstill detection is required since the direction of rotation of the F position encoder is evaluated for the detection of the modulo jump. The following applies: if a standstill is detected, there is no evaluation of the direction of rotation. The standstill evaluation is performed the same as for the FB SSTILL (FB 15). 22 V 1.0a, Entry ID:

23 5 Realizing the Functionalities Modulo evaluation If the direction of rotation is positive (forward) and the current position is smaller than the previous position, then a modulo error is reported. If the direction of rotation is negative (backward) and the current position is larger than the previous position, then a modulo error is reported. V 1.0a, Entry ID:

24 5 Realizing the Functionalities 5.4 Safe direction detection What can the block perform? The block indicates the direction of rotation of the encoder. Parameter description FB DIR (FB 18) Input parameters Data type Description VELO_ACT INTEGER Current safe speed of the encoder. VELO_TOL INTEGER Tolerance value (standstill defining value range) OV_VELO BOOL 1: speed value outside of the permitted value range Automatically set by the encoder. ACK BOOL 1: error acknowledgement or reintegration Output parameters Data type Description FORW BOOL 1: Encoder rotating in positive direction BACK BOOL 1: Encoder rotating in negative direction ERR_DIR BOOL Error bit 1: Error (OV_VELO = 1) Description of the realization Since the encoder can still output various values in standstill when it is in zero (for example, due to the noise of the analog inputs), in this state this can lead to a flicker of the FORW and BACK bits. To avoid this, you can indicate a VELO_TOL tolerance value. Only if a speed value is larger than VELO_TOL, are the FORW (positive direction) or BACK (negative direction) bits set. If VELO_TOL was indicated as positive If VELO_TOL was indicated as negative Two s complement of VELO_TOL 24 V 1.0a, Entry ID:

25 5 Realizing the Functionalities The evaluation for the negative direction of rotation (BACK) is performed in the same way. You must not use the FB DIR (FB18) for the evaluation of a safe standstill detection! WARNING In case of VELO_TOL = 0, the bits FORW und BACK will always be false. Do not interpret this as a safe standstill! Set for VELO_TOL a value unequal of zero. V 1.0a, Entry ID:

26 6 Required Components 6 Required Components Hardware components Component Type MLFB / order information No. Manufacturer Power supply PS307 5A 6ES7-1BA00-0AA0 1 SIEMENS S7-CPU, can be used for safety applications Position encoder, can be used for safety applications CPU315F-2DP 6ES7315-6FF01-0AB0 1 SIEMENS CDH 75 M SN CDH75M TR Electronic Note You can also use similar hardware components. In this case, observe possibly changed resolutions for the position encoder and that it is approved for safety relevant tasks. Configuration software and tools Component Type MLFB / order information No. Manufacturer SIMATIC STEP 7 V5.5 6ES7810-4CC07-0YA5 1 SIEMENS SIMATIC Distributed Safety V5.4+SP5 6ES7833-1FC01-0YA5 1 SIEMENS 26 V 1.0a, Entry ID:

27 7 Installation 7 Installation Note This chapter is only necessary if you wish to set up the offered S7 example project. Hardware installation The respective hardware consists of: F-CPU (incl. power supply) F encoder PS 307 / CPU 315F-2DP N L1 PE L1 N L+ M L+ M L+ M L+ M DP F encoder L+ M Note The electric wiring of the F encoder can be found in the appropriate manual. Software installation No. 1 Install STEP 7 2 Install Distributed Safety afterwards Action 3 To be able to use the S7 project that is also offered, download the zip file into a local directory of the Windows Explorer. in the SIMATIC Manager go to File -> Retrieve and select the zip file. Follow the instructions Password The password for the STEP 7 project is siemens V 1.0a, Entry ID:

28 8 Operating the Application 8 Operating the Application Important notes It is essential that you observe the following warning: WARNING The provided STEP 7 project has the inputs and outputs of the offered failsafe function blocks already switched with actual parameters. On the one hand there are safe quantities provided by the F position encoder, on the other there are flags (and thus non-safe quantities), that can be controlled through a VAT_1 variable table. In this way, VAT_1 was only prepared for demonstration purposes, so that once the F position encoder is integrated on the PROFIBUS DP, you can quickly get familiar with its functionality. For example, by turning the shaft, you can directly monitor in VAT_1 how the numerical values (multi turn) for the revolutions, angle (single turn) and speed are changing. However, under no circumstances must the STEP 7 project, provided in this way, be integrated in a real practical application! The flags in this case have to be replaced, for example, by real signals and individual limit and tolerance values, and for the process. The input quantities, specified as absolute numbers in the provided STEP 7 project, also have to be adjusted to the individual framework conditions for a real practical application! Example for testing with VAT_1 Once the F position encoder is integrated in the PROFIBUS DP and the S7 program is loaded in the F-CPU, you can monitor and control the variables with VAT_1 for demonstration purposes (whilst observing the above warning). The figure on the next page shows this on the example of FB F_POSITION (FB 17): The framed variables indicate the positions that define a danger range. With the VAT_1 the numerical values are transferred to FB F_POSITION (FB 17). Entries 10 ( MULTI ) and 11 ( SINGLE ) show the current position. Whilst the F position encoder (entry 7 of VAT_1 BACK = true ) is rotating backward, the current position is in the defined danger range. This is displayed by DANGER_RANGE = true (entry 19 of VAT_1). 28 V 1.0a, Entry ID:

29 8 Operating the Application V 1.0a, Entry ID:

30 9 Norm Considerations 9 Norm Considerations Consideration in accordance with IEC According to the manufacturer s details sub-systems 1 and 2 have a SIL (Safety Integrity Level) CL 3 (claim) each. If sub-system 3 is established in a way so that there is a SIL CL 3, then the basic requirement for realizing a SIL 3 for the safety function is fulfilled. SRCF Function block 1 Detect Function block 2 Evaluate Function block 3 Response SRECS SIL CL 3 SIL CL 3 SIL CL x Sub-system 1 Sub-system 2 Sub-system 3 F encoder DP F-CPU Depending on application The following applies for the entire PFH D value: PFH D (SRCF) = PFH D (TS1) + PFH D (TS2) + PFH D (TS3) + PFH TE with TS: sub-system PFH TE : Probability of dangerous transmission error for digital communication processes (here: communication of F-CPU through PROFIBUS). TE stands for Transmission Error. The PFH D values are provided by the manufacturers of the components; the PFH TE value can be included once in the calculation with Parameters PFH D SIL 3 according to IEC Manufacturer PFH D (F position encoder) PFH D(F-CPU) PFH D(TS3) PFH TE (F communication) TR Electronic SIEMENS Depending on the application 9 SIEMENS 30 V 1.0a, Entry ID:

31 9 Norm Considerations Therefore, the following applies: PFH D (SRCF) = PFH D (TS3) PFH D (SRCF) = PFH D (TS3) The correlation between PFH D and SIL is available in table 3 of IEC 62061: Safety integrity level (SIL) Probability of a dangerous failure per hour (PFH D) to < to < to < 10 5 In addition, each sub-system has to fulfill a SIL CL x for SIL x. Consideration in accordance with ISO Table 4 of ISO :2006 shows the relation between the performance level (PL) and the safety integrity level (SIL). Therefore, a PL e according to ISO :2006 can be assumed if the SIL 3 is achieved for the safety function. In this example, this mainly depends on the realization of the SRP/CS Response. PL e PL e PL x SRP/CS Detect SRP/CS Evaluate SRP/CS Response PL Detect PL Evaluate PL Response Here, the following also applies: PFH D (SRCF) = PFH D (TS3) PFH D (SRCF) = PFH D (TS3) The relation between PFH D and SIL can also be found in table 3 of IEC (see above). V 1.0a, Entry ID:

32 10 History 10 History Version Date Modification V /2011 First edition V 1.0a 07/2013 Additional important note in chapter 5.4 V 1.0b 02/2017 Change I7.0 to I V 1.0a, Entry ID: