Allen-Bradley GuardPLC 1753, Safety Reference Manual

Page: 48 / 120

48 Publication 1753-RM002C-EN-P - September 2008
Chapter 4 GuardPLC Controller and GuardPLC I/O Output Channels
Relay Outputs in the
1753-OW8 Module
The information in this section applies to the relay outputs of the
1753-OW8 module.
Test Routines
The modules are automatically tested during operation. These are the
essential test functions.
•
Read back the output signal of the switching amplifiers before
the relays.
•
Test the switching of the relays with positively guided contacts.
•
Test the integrated redundant safety shutdown.
The operating voltage of the entire system is monitored, de-energizing
all outputs at an undervoltage of <13V.
At the 1753-OW8 module, the outputs are equipped with three safety
relays; two relays with positive guided contacts and one MSR type
enabling the outputs to be used in safety shutdowns.
Reaction To Error
If a faulty signal is detected, all contact outputs of the module are set
to the safety (0) state via the safety switches in accordance with the
closed-circuit principle. This is also indicated by the FAULT diagnostic
LED indicator.
Relay Outputs in the 1753-OW8
I/O Bus WD L+
T
T
T
8 channels
ERR
RUN
Test
8
1
O1...
3.15 AT
...O8
3.15 AT