Rockwell Automation 1791ES-IB16 Guard I/O EtherNet/IP Safety Modules - Manual (Page 26)

26 Rockwell Automation Publication 1791ES-UM001D-EN-P - May 2013
Chapter 2 Understand the Operation of Safety Functions
Safety Input Fault Recovery
If an error is detected, the safety input data remains in the off state. The
procedure for activating the safety input data again is as follows.
1. Remove the cause of the error.
2. Place the safety input (or safety inputs) into the safety state.
The safety input status turns on (fault cleared) after the input-error latch
time has elapsed. The I/O indicator (red) turns off. The input data can
now be controlled.
Input Delays
On-delay - An input signal is treated as logic 0 during the on-delay time (0…126
ms, in increments of 6 ms) after the input contact’s rising edge. The input only
turns on if the input contact remains on after the on-delay time has elapsed. This
helps prevent rapid changes of the input data due to contact bounce.
Figure 10 - On-delay
Off-delay - An input signal is treated as logic 1 during the off-delay time (0…126
ms, in increments of 6 ms) after the input contact’s falling edge. The input only
turns off if the input contact remains off after the off delay time has elapsed. This
helps prevent rapid changes of the input data due to contact bounce.
Figure 11 - Off-delay
44094
ON
OFF
ON
OFF
Remote I/O
Data Safety
Input
Input Signal
ON-delay On-delay
ON
OFF
ON
OFF
Input Signal
Remote I/O
Data Safety
Input
44094
OFF
ON
OFF Safety Input
Input Signal
OFF-delay
Remote I/O Data
44095
Remote I/O Data
Safety Input
Off-delay
Input Signal
ON
OFF
ON
OFF