Siemens Simatic Manual

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Contents

Fail-safe function blocks for storage and retrieval machinesS7-Distributed Safety/SIMATIC Safety - fail-safe function blocks for storage and retrieval machines - 3-7 -3.1.6 Using data blocks/multi-instancesNoteAll of the data blocks listed in this manual, with the exception of the DBs perma-nently assigned to F_ENDZONE_DBxxxxx, are used arbitrarily. The fail-safefunction blocks of the "RBG_Failsafe_DS_V5_4"/"RBG_Failsafe_TS_V13" librarycan be combined with any data block still not assigned in the user programNoteWith the exception of F_SCALE_DINT, ASRS blocks can be called as multi-instance without any restrictions. It is mandatory that F_SCALE_DINT is calledwith its own instance data block.3.1.7 Response timesThe response times required must be taken from the relevant risk assessment. This involves a blocklibrary that can be universally used. This is the reason that a specific value cannot be specified for theresponse times of the individual safety functions.Safety notes and instructionsDepending on the required response time, parameters T_SAMPLE (and thereforethe call interval of the safety program) – as well as POS_SI_T_SAMPLE – mustbe parameterized in the ASRS blocks so that under no circumstances are theyshorter than the maximum permitted response time. It should be taken into ac-count that also the hardware components used influence the response time. Thes7fcoti table can be used to calculate the response time from the sensor to theactuator.3.1.8 Execution timesThe values of the execution times of the fail-safe ASRS blocks running on the supported F-CPUs canbe taken from the table in the Appendix I). These values are required to calculate the response time.Safety notes and instructionsIt is the users responsibility to interconnect and parameterize the ASRS blocksaccording to the standards applicable for their particular application. This is espe-cially true for the test rates/intervals for the brake test and the overload/slackcable detection – as well as all load and velocity limits.Safety notes and instructionsAll position limits must be selected so that when these are exceeded the particu-lar axis can come to a standstill before the end of the travel range. The value tobe parameterized is also dependent on the maximum velocity to be expected forthe specific application – as well as the maximum possible and permitted decel-eration.