I have three older Robodrills wit the 16i control that I have added additional M-codes and ladder logic to open/close a side door and work holding vices. Two of the three mills work and execute the M-code/custom ladder fine. The third is a sister to the other two (purchased at the same time) and none of the M-codes for opening and closing the door or work holding vices work. I've double check the wiring to the solenoid. Are there any parameters or keep relay parameters that turn on the custom ladder program? Any other ideas would be appreciated.