What Is The Difference Between The Different Operating Modes Of The PLCs' CPU Unit (i.e., PROGRAM Mode, RUN Mode, And MONITOR Mode)?

In PROGRAM mode, the CPU Unit is stopped. User programming can be created or modified, memory can be cleared, programs can be checked, programs can be debugged, and I/O memory tables can be created or modified.

 

In MONITOR mode the CPU Unit is running. I/O is processed in the same way as in RUN mode. The operating status of the CPU Unit can be monitored, bits can be force-set/reset, the set values and present values of timer and counter instructions can be modified, and the present values of word data can be modified. MONITOR mode is used for system adjustments during trial operation.

 

RUN mode is used for normal system operation. The operating status of the CPU Unit can be monitored, however bits cannot be force-set/reset, and present values and set values cannot be modified using Programming Devices.
The operating mode can be changed using a Programming Device or by sending a command using Host Link communications.