Rockwell Automation Publication 1791ES-UM001G-EN-P - November 2016 89
Configure the I/O Modules Chapter 5
Follow these steps to configure the module inputs.
1. Click the Input Configuration tab.
2. For Point Operation Type, choose one of these values and a value for 
Discrepancy Time if set to Equivalent or Complementary:
•Single 
Inputs are treated as single channels. In many cases, dual-channel 
safety inputs are configured as two individual single channels. This 
configuration does not affect pulse testing because it is handled on an 
individual channel basis.
•Equivalent
(1)
 
Inputs are treated as a dual-channel pair. The channels must match 
within the discrepancy time or an error is generated.
• Complementary
(1)
Inputs are treated as a dual-channel pair. They must be in opposite 
states within the discrepancy time or an error is generated.
3. For Point Mode, choose one of these values for each point and refer to 
the Safety Input Parameters table for additional information:
• Not Used - Safety input channel is disabled
• Safety Pulse Test - Safety input is configured for pulse test operation
• Safety - The safety input is used with a safety field device
Safety Input Error Latch Time 0…65,530 ms
(in increments of 10 ms)
Default is 1000 ms. The purpose for latching input errors is to make sure that intermittent faults that can only 
exist for a few milliseconds are latched long enough for the controller to read. The amount of time to latch the 
error must be based on the RPI, the safety task watchdog, and other application-specific variables.
(1) There are eight test outputs on 1791ES-IB8XOBV4, 1732ES-IB8XOB8 and 1732ES-IB8XOBV4 modules, 16 test outputs on 1791ES-IB16 and 1732ES-IB16 modules, and 12 test outputs on 
1732ES-IB12XOB4 and 1732ES-IB12XOBV2 modules.
Table 23 - Typical Safety Input Parameters (Continued)
Parameter Name Value Description
(1) If you configure discrepancy time on safety I/O modules, it masks input inconsistent faults from the GuardLogix safety 
instructions. GuardLogix can read status to obtain this fault information.