Run-time enviroment 		Return to Introduction  Previous page  Next page

 

The PLC runtime environment is firmware which provides the operating systemservices and library functions associated with the PLC. In the RUN mode,the PLC firmware runs as real-time executive which processes the (LadderLogic) instructions that have been loaded into the program RAM area. The program runs in a continuous loop which consists of the following major phases:

 

•Input read and output write scan
•Housekeeping
•Program scan (logic solve).