Fail-Safe Function Blocks For Storage And Retrieval Machines; Overview; Safety Notes And Instructions; Fail-Safe Blocks - Siemens Simatic Manual

Fail-safe function blocks for storage and retrieval machines

3 Fail-safe function blocks for storage and retrieval
machines

3.1 Overview

3.1.1

Safety notes and instructions

As stated in Chapter 2.5, the fail-safe function blocks for storage and retrieval machines cover the
requirements laid down in EN528:2008.
The safety integrity level of the various safety functions is only obtained through the correct intercon-
nection. For this reason, the correct interconnection of each fail-safe function block in this library and
the overall functionality of the safety functions must be validated against the relevant application-
specific hardware and software based on positive and negative tests.
The tests should first be carried out in a part of the system where there is sufficient clearance to the
fixed end stops (buffers). It must also be ensured that the system can be safely shutdown if an emer-
gency occurs during the various tests.
The tests should be documented, for example, using trace recordings, so that limit value violations,
shutdown conditions and stopping distances can be clearly identified. This therefore allows a clear
statement to be made about the correct function of each individual safety function.
3.1.2

Fail-safe blocks

The library "RBG_Failsafe_DS_V5_4" for SIMATIC S7 Distributed Safety Programming or
"RBG_Failsafe_TS_V13" for SIMATIC STEP 7 Safety Advanced includes the following blocks:
F_SAFE_POS
F_SLP_MONITOR
F_ENDZONE_DB
F_BRAKE_TEST
F_LOAD_MONITOR
F_SBR_MONITOR
F_SCALE_DINT,
SCALE_DINT
F_MIN_MAX
The following fail-safe blocks are additionally required that are programmed using SIMATIC
S7 Distributed Safety Programming:
F_TP
F_W_BO
S7-Distributed Safety/SIMATIC Safety - fail-safe function blocks for storage and retrieval machines
Function block to generate a safety-related position and veloc-
ity actual value
Function block for safe position monitoring
Function block to monitor the velocity at the end of the travel
range
Function block to perform a safe brake test in conjunction with
the SBT drive function
Function block to detect overload and slack cable condition
with the option of testing the measuring device
Function block to monitor the brake ramp
Blocks to safely scale 32-bit values
Function to select minimum/maximum value
Generates a pulse with a specific duration
Converts a value in the WORD format into 16 pieces of data in the
bool data type
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