Process and apparatus for controlling a programmable controller with efficient identification of operation completion.

摘要

A master programmable controller (2) is linked to one or more processing units (4, 14) by a network that enables communication to or from the units under system program control. The communication is based on data link instructions that are organized in blocks, as a series of a one or more data link instructions for corresponding units, and are accessed for execution in a sequence established by a sequence program, stored at the programmable controller (2). One or more of the data link instructions have a corresponding operation completion flag addressing instruction for specifying the address of a flag that is set where the respective operations of the data link instructions are complete. The efficient programming and execution of the sequence program is provided by assembling the data link instructions that define communications with one or more units (4,14) into a group that is served by a single operation completion flag addressing instruction. The master programmable controller memory (11) has stored therein information concerning the operating condition, including completion status, of each of the one or more grouped data link instructions. <IMAGE>