Normally the MODE switch is binary decoded switch, it is usually an indication the PMC is not running, I don't have my BMI book here for the 0, but you need to check the G register lines for the output of the mode switch, if you can either call up the ladder on screen or look at the diagnostic X inputs and see if you see a bit pattern change when turning the switch.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.