door mania

I am using The Learning Pit Logix Pro Simulator (AB ). In the door simulator exercise #4 the instruction is to modify the program so that if the overhead door is opening, pressing the N.O. close button will immediattley stop the door. Door movement will remain halted when the close button is released. The same criteria applies if the door is closing and the open button is pressed. I have used
latch/unlatch, internal bits, and one time rising instructions in various configurations without success. The door reverses direction instead of stopping. any suggestions will be greatly appreciated.

So you need to press a button, wait until it's released, then take action.

XIC stop OSR temp OTL hold
XIO sto XIC hold OTL down OTL hold

I may be wrong but it seems like you may be blindly trying instructions. Have you made a 'state diagram' of this sequence? Obviously you will have at least three states, Opening, Closing and Stopped. If a transition is caused my making a pushbutton but the output conditions continue when the pushbutton is released then you will need an intermediate transition state.

In your example let's say you are in the "Opening" state. Pressing the "Close" pushbutton transitions to a "Stopping" intermediate state. The door is no longer commanded to move. Releasing the "Close" pushbutton transitions to the "Stopped" state. The same transitions take place if you were closing. ("Closing" (then Open pressed) -> "Stopping" (then Open Released) -> "Stopped").

Next will be how to implement "State Diagrams" in ladder logic. Once you have this skill (analysing to State Diagrams the translating to Ladder Logic) you can tackle a vast variety of projects.