Block Interaction; Overview; Signal Flow Between The Components; Automation Task - Siemens Simatic Manual

Block interaction

4 Block interaction

4.1 Overview

This chapter explains the most important points that must be taken into account when using the
fail-safe function blocks for storage and retrieval machines. Further, the necessary interconnec-
tion options between the blocks are shown in the form of examples.
The block package has a modular structure, and can be individually adapted to address the par-
ticular application.
The blocks implement a predefined autonomous subfunction. Depending on the particular ma-
chine, not all of the blocks in the library will always be required.
If additional functions are required to specifically control your application, you must create these
yourself by adding additional fail-safe functions. The signals of these functions are then in turn
interconnected with the ASRS blocks.
Safety notes and instructions
The safety-relevant times and the interconnection of inputs and outputs must be
parameterized so that they are compliant with the guidelines and directives appli-
cable for the particular plant or system. Further, they must be checked at the
plant or system to ensure that the relevant requirements are satisfied.

4.2 Signal flow between the components

The signal flow between the interfaces of the blocks, which can directly interact with one anoth-
er, is shown in the following overview. The additional inputs that are not connected below,
should be parameterized according to the description above. However, for reasons of transpar-
ency, they are not interconnected in the following overview as they do not exchange information
between the blocks, but are individually parameterized for each block.
4.2.1

Automation task

In the following overview of the block interconnections, a hoisting gear is monitored to ensure
that it only moves in a defined range.
Either block F_SLP_MONITOR or block F_ENDZONE is used. If F_ENDZONE is used, then
there is also the option of only being able to travel into the end zones with a reduced velocity.
The F_SAFE_POS block supplies the safety-relevant position and velocity required for the
blocks mentioned above.
Blocks F_SCALE_DINT and SCALE_DINT scale the 32-bit value of the absolute measuring
system to SLU unit.
The hoisting gear is monitored for overload and slack cable using F_LOAD_MONITOR.
The F_BRAKE_TEST block is responsible for testing the functioning of the hoisting gear brakes.
If F_LOAD_MONITOR, F_BRAKE_TEST or F_SLP_MONITOR/F_ENDZONE identify that a lim-
it value has been violated, then a signal to initiate a stop response is also generated, and the
SLS threshold for retraction is set to the value that can be parameterized at the block, which is
internally monitored.
After SS1 has been selected, block F_SBR_MONITOR monitors as to whether the drive brakes
with the configured down ramp. If this is not the case, then a signal to initiate STO is generated.
By AND'ing all of the relevant enable signals of the blocks, the signal to initiate a stop response
(e.g. SS1) can be generated for the drive.
For the retraction function of blocks F_ENDZONE, F_LOAD_MONITOR and F_SLP_MONITOR,
by AND'ing the corresponding MOVE_POSITIVE_OK / MOVE_NEGATIVE_OK signals, only
that direction is permitted that allows the axis to move away from the end zone.
For the F_BRAKE_TEST block, using the RELEASE_DIR output, the hoisting gear can be pre-
vented from traveling upwards if the brake test was unsuccessful.
S7-Distributed Safety/SIMATIC Safety - fail-safe function blocks for storage and retrieval machines
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