Chapter 5 POU and Task Events that are triggered in the following ways: - Motion event (Motion control task) - Rising edge or falling edge of local input points (I0~I7 and I10~I17) - CANopen SYNC signal - Z pulse rising edge of incremental encoder 1 or encoder 2 The condition for the second-time execution is ignored when the condition required for execution of the event task is met again before the event task is completed. The period before an event task is completed is the course while the event task is being executed or is waiting to be executed. Executing Task According to Priority The controller cannot perform multiple tasks simultaneously.
Every task must be given a priority level and they are executed according to preset priorities. Priority level can be set within the range of 1 to 24. (1 is the highest priority and 24 is the lowest priority.) The priority level of each task must be unique. The task with higher priority takes priority to perform. The high-priority task can interrupt the low-priority task. We recommend that the task which has a high requirement of real time should be given a high priority and the task which has a low requirement of real time should be given a low priority. The priority of the default motion control task built in ISPSoft is 1 by default.
Executing two tasks at the same time (Cyclic and freewheeling) Priority High Time interval between tasks Time interval between tasks Cyclic task ( ) Priority 1 Task execution condition met 1 2 Task execution finished Task execution condition met Task execution finished 5 6 Task execu tion tim e Task execu tion t im e Task e xecut ion time Fre ewh eelin g task ( ) Priority 2 Task execution condition met Task execution finished Task execution condition met Task execution condition met 3 7 8 4 Task execution finished Low System processing System pr ocessing System processing System processing The execution conditions for the cyclic task and freewheeling task are met at the same time.
The cyclic task is executed first because of its higher priority. When the cyclic task execution is finished, the freewheeling task execution starts. The controller will execute the system processing if there is no other task after the execution of the freewheeling task is completed. 5-9 IO User program IO User program IO User program Pause User program Pause IO User program IO User program