Queue function making method for programmable-logic controller, involves processing received command, if controller does not processes command, and retrieving commands with priority, after controller has completed processing of commands

摘要

The method involves receiving a command from a terminal (1), and judging whether a programmable-logic controller (PLC) (3) processes the command. The received command is processed, if the PLC does not processes the command. The received command is saved in a command queue (32), if the PLC processes another command. The commands are retrieved with the highest processing priority, after the PLC has completed processing of the commands. A network bus (2) is provided for connecting the PLC and the terminal. An independent claim is also included for a programmable-logic controller comprises a microcontroller unit.