Rockwell Automation 1791DS-IBxxxx Guard I/O DeviceNet Safety Modules - Manual (Page 37)

Rockwell Automation Publication 1791DS-UM001J-EN-P - May 2013 37
Understand the Operation of Safety Functions Chapter 2
Dual-channel Setting
When the data of both channels is in the on state, and neither channel has a fault,
the outputs are turned on. The status is normal. If a fault is detected on one
channel, the safety output data and individual safety output status turn off for
both channels.
Figure 20 - Dual-channel Setting (not to scale)
Safety Output Fault Recovery
If a fault is detected, the safety outputs are switched off and remain in the off
state. Follow this procedure to activate the safety output data again.
1. Remove the cause of the error.
2. Place the safety output (or safety outputs) into the safety state.
The safety output status turns on (fault cleared) when the output-error
latch time has elapsed. The I/O indicator (red) turns off. The output data
can now be controlled.
ON
OFF
OUT0
Safety Output
Status 0, 1
OUT0
OUT1
OUT1
Safety Output
Status 0, 1
Fault Detection
Error
Detected
Remote
I/O
Data
Remote
I/O
Data
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
Normal Operation