Not familiar with your driver's, but if you want to use the safety circuit on the UB1 you must use a pin between x103-x110. These are (at least default operation) 24V NPN pins, so the X103 pins pull up to +24V and watch for when it is connected to 0V. I certainly wouldn't recommend connecting any of the X input pins to +5V, just because they are labelled input doesn't mean you can just send them logic levels.

I really suggest thoroughly reading through the UB1 manual and digesting every section, it's quite easy to screw it up and waste quite a bit of money.