Safety Modules Owner manual

Rockwell Automation Publication 1791ES-UM001D-EN-P - May 2013 23
Understand the Operation of Safety Functions Chapter 2
The following table shows the relation between input terminal states and
controller input data and status.
Dual-channels, Equivalent
In Equivalent mode, both inputs of a pair must typically be in the same
(equivalent) state. When a transition occurs in one channel of the pair, prior to
the transition of the second channel of the pair, a discrepancy occurs. If the
second channel transitions to the appropriate state prior to the discrepancy time
elapsing, the inputs are considered equivalent. If the second transition does not
occur before the discrepancy time elapses, the channels will fault. In the fault state
the input and status for both channels are set low (off ). When configured as an
equivalent dual pair, the data bits for both channels will always be sent to the
controller as equivalent, both high or both low.
Table 2 - Terminal Input Status and Controller I/O Data
Dual-channel Mode Input Terminal Controller Input Data and Status Dual- channel
Resultant
Data
Dual-channel
Resultant
Status
IN0 IN1 Safety
Input 0 Data
Safety
Input 1 Data
Safety
Input 0 Status
Safety
Input 1 Status
Dual-channels, Equivalent OFF OFF OFF OFF ON ON OFF Normal
OFF ON OFF OFF OFF OFF OFF Fault
ON OFF OFF OFF OFF OFF OFF Fault
ON ON ON ON ON ON ON Normal
Dual-channels,
Complementary
OFF OFF OFF ON OFF OFF OFF Fault
OFF ON OFF ON ON ON OFF Normal
ON OFF ON OFF ON ON ON Normal
ON ON OFF ON OFF OFF OFF Fault