BECKHOFF KL6904 - Manual (Page 34)

Operation
32 KL6904
4.2.8.1 Activating and configuring the block inputs
The following parameters can be set:
Deactivated: The input is not used
Single-channel: The inputs are linked independent of each other
Two-channel:
The inputs are monitored for equality or inequality, depending on the contact type
setting. A Discrepancy Time can be set for monitoring the two inputs for simultaneous
switching.
Make Contact: Contact type setting
Break Contact Contact type setting
The inputs are now activated.