Discrepancy time monitoring

The safety option carries out discrepancy time monitoring for input pairs in the two-channel equivalent and two-channel non-equivalent connection types. The discrepancy time monitoring verifies whether the two input signals are delivering fault-free levels that match the switching state of the sensor. A deviation is tolerated for the parameterized discrepancy time. An input fault occurs if the deviation from the expected signal state exceeds the discrepancy time. The discrepancy time can be adjusted for each input pair via a parameter.

The safety option carries out a switch test function for input pairs in the two-channel equivalent and two-channel non-equivalent connection types in order to verify the connected switch for correct switching behavior following a detected discrepancy error. The switch test function can be activated and deactivated for each input pair via a parameter. The switch test function assumes that the switch contacts are moved into the opened/activated state after the occurrence of the discrepancy error so that the two input signals assume the required state for the switch test:

• Connection type two-channel equivalent
• F-DI. = logical "0"
• F-DI. + 1 = logical "0"

• Connection type two-channel non-equivalent
• F-DI. = logical "0"
• F-DI. + 1 = logical "1"

Only in this case can the discrepancy error be acknowledged; acknowledgment is otherwise impossible and the input remains in the discrepancy error.