
Rockwell Automation Publication 1756-UM013B-EN-P - October 2019
127
Application and Wiring Examples for Safety Modules
Appendix C
When the module is wired as shown, it is suitable for applications that are rated
up to, and including,
Category 4
and
PLe
as defined in ISO 13849-1.
To achieve that suitability rating, you may have to perform diagnostic testing and
monitoring of the safety function. One diagnostic test method is to configure the
safety output channel for Safety Pulse Test to test the circuit for short circuits to
24V DC.
For Cat.4 applications, if your application remains in safe state, that is, the output
is off, for a prolonged duration, we recommend that you take one of these actions:
• Apply output monitoring at the actuator. The monitoring can be direct or
indirect.
• Limit the safe state to no more than 24 hours.
• Conduct functional test if safe state dwell time increases.
DC(+)
DC(-)
DC(+)
DC(-)
OUT0-P
OUT1-P
OUT4-P
OUT3-P
OUT2-P
OUT5-P
OUT6-P
OUT7-P
OUT0-M
OUT1-M
OUT2-M
OUT3-M
OUT4-M
OUT5-M
OUT6-M
OUT7-M
+ -
Connection Pairs
When you use dual-channel sourcing wiring on the 1756-OBV8S
module, you must connect the devices to dual-channel connection
pairs. For example, the devices are connected to channels 4 and 5
because they are a connection pair. These channels are
dual-channel connection pairs:
• Channels 0 and 1 (shown)
• Channels 2 and 3
• Channels 4 and 5
• Channels 6 and 7
DC –
24
V
DC
SELV/PELV-listed power
supply
Channel Connections
This wiring example shows connections to Safety Output 0 P and
Safety Output 1P. You are not limited to using channels 0 and 1 in
this mode. You can use all channel pairs as determined by your
application.
We
strongly recommend
that, if you have a direct connection
between the safety output module and an input module and
those modules are powered by separate power supplies, you
connect module DC- and actuator DC- together. This practice helps
to eliminate grounding float from disrupting diagnostics.
M
K
K