Using Data Blocks/Multi-Instances; Response Times; Execution Times - Siemens Simatic Manual

Fail-safe function blocks for storage and retrieval machines
3.1.6

Using data blocks/multi-instances

Note
All 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-safe
function blocks of the "RBG_Failsafe_DS_V5_4"/"RBG_Failsafe_TS_V13" library
can be combined with any data block still not assigned in the user program
Note
With 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 called
with its own instance data block.

3.1.7 Response times

The response times required must be taken from the relevant risk assessment. This involves a block
library that can be universally used. This is the reason that a specific value cannot be specified for the
response times of the individual safety functions.
Safety notes and instructions
Depending on the required response time, parameters T_SAMPLE (and therefore
the call interval of the safety program) – as well as POS_SI_T_SAMPLE – must
be parameterized in the ASRS blocks so that under no circumstances are they
shorter than the maximum permitted response time. It should be taken into ac-
count that also the hardware components used influence the response time. The
s7fcoti table can be used to calculate the response time from the sensor to the
actuator.

3.1.8 Execution times

The values of the execution times of the fail-safe ASRS blocks running on the supported F-CPUs can
be taken from the table in the Appendix I). These values are required to calculate the response time.
Safety notes and instructions
It is the users responsibility to interconnect and parameterize the ASRS blocks
according 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/slack
cable detection – as well as all load and velocity limits.
Safety notes and instructions
All 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 to
be parameterized is also dependent on the maximum velocity to be expected for
the specific application – as well as the maximum possible and permitted decel-
eration.
S7-Distributed Safety/SIMATIC Safety - fail-safe function blocks for storage and retrieval machines
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