Chapter 5 POU and Task The event task interrupts the freewheeling task execution because the event task has the highest priority and the execution condition for the event task is met. executed yet when the event task execution is completed. The controller continues to execute the part of the low-priority freewheeling task, which has not been The freewheeling task execution is completed. The controller executes the cyclic task since the cyclic task request in ⑦ is not responded yet. ○ 11 The cyclic task execution is completed. The controller executes the system processing due to no other task request.
5.3.2 Tasks in the Project Management Area The POUs which are assigned to tasks are listed in the Tasks section in the project management area, and the POUs which are not assigned to tasks are not listed in the Tasks section. The order in which the POUs listed in a task section are arranged is the order in which the POUs are executed. Take the project for an AH500 series CPU module below for example. There are 9 POUs of the program type. The assignment of the POUs of the program type to tasks is as follows. *. The setting of the condition for an interrupt will be introduced in section 5.5. Please refer to instructions for PLCs for more information.
5-11 Task name POU Execution Not assigned Prog2 and Prog3 Owning to the fact that Prog2 and Prog3 are not assigned to tasks, Prog2 and Prog3 are not executed. Cyclic (0) Prog6 and Prog4 The smaller the task number is, the earlier the task is executed. As a result, the order in which Prog6, Prog4, Prog5, and Prog7 are scanned is Prog6Prog4Prog5 Prog7. Cyclic (1) Prog5 and Prog7 I/O interrupt (0) Prog1 If the condition of the interrupt is met, Prog1 will be executed once. Timed interrupt 1 (253) Prog8 and Prog9 Timed interrupt 1 is triggered every specific period of time. The order in which Pog8 and Prog9 are executed is Prog8Prog9.