Boolean Register

Good evening,

I am trying to code my UR3e so that when a specific force threshold is reached, the robot is paused. I wanted to use an input boolean register in my code to do so, but without being set from a switch connected to the control box but rather having the value be set in the code itself in an event ( interrupt ). I am unable to set/use the input register in my code and am being told it is undefined. So, I wanted to ask how I can manipulate this register manually and be able to get its value.

Thank you for your time.