STARTING METHOD FOR EVENT-DRIVEN FUNCTION BLOCK, EVENT- DRIVEN CONTROLLER, COMPILER FOR EVENT-DRIVEN FUNCTION BLOCK, AND COMPILER FOR EVENT-DRIVEN CONTROL PROGRAM

摘要

PPROBLEM TO BE SOLVED: To efficiently start an event-driven function block for executing given processing when an event occurs, and to improve the readability of all control system programs. PSOLUTION: A binary data type indicative of whether there is an event or not is defined, and an event variable is defined in the data type. When an event-driven function block FB is called, an upper program searches out presence/absence of an event variable in the preceding function block FB, and in the case of being set in the presence of an event, an event input variable of the called function block FB is set in the state of presence of an event. After the function block FB is called, an event output of the preceding function block FB is set eventless, and in the called function block FB, an event input variable is set eventless after given processing is executed and all reference to the event input variable is finished. PCOPYRIGHT: (C)2003,JPO