Siemens SINUMERIK 840D sl Function Manual page 1150

Detailed description
2.12 Block descriptions
2.12.8 FB 10: Safety relay (SI relay)
Description of Functions
The SPL block "Safety relay" for "Safety Integrated" is the PLC equivalent of the NC function
of the same name. The standard SPL "Safety relay" block is designed to support the
implementation of an emergency stop function with safe programmable logic. However, it
can also be used to implement other similar safety functions, e.g., control of a protective
door. The function contains 3 input parameters (In1, In2, In3). On switchover of one of these
parameters to the value 0, the output Out0 is deactivated without delay and outputs Out1,
Out2 and Out3 deactivated via the parameterized timer values (parameters TimeValue1,
TimeValue2, TimeValue3). The outputs are activated again without delay, if inputs In1 to In3
take the value 1 and a positive edge change is detected at one of the acknowledgement
inputs Ack1, Ack2. To bring the outputs to their basic setting (values = 0) after booting, the
parameter "FirstRun" must be configured as follows. The parameter "FirstRun" must be
switched to the value TRUE via a retentive data (memory bit, bit in data block) on the first
run after control booting. The data can be preset, e.g., in OB 100. The parameter is reset to
FALSE when FB 10 is executed for the first time. Separate data must be used for parameter
"FirstRun" for each call with its own instance.
The corresponding NCK-SPL-component is described in:
References:
/FBSI/Description of Functions, Safety Integrated
Simplified block diagram in CSF
The figure below shows only one acknowledgment input Ack1 and one delayed deactivation
output Out1. The circuit for Ack2 and the other delayed outputs are identical. The parameter
FirstRun is also missing in the function diagram. The mode of operation is described above.
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Basic logic functions: PLC Basic program powerline (P3 pl)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0