Chapter 14 Sequential Function Chart (b) STEP_1 is activated for less than two seconds. After control is passed to the next step, the delay of Action1 will still be measured. Two seconds has elapsed before Action1 is executed. However, after the control is passed to the next step, the delay of Action2 will not be measured, and Action2 will not be executed. L (Limit) When a step is activated, the L action associated with the step is executed. If the L action has been executed for a certain amount of time before control is passed to the next step, the execution of the L action will stop automatically, and the system will execute a final scan.
If the control is passed to the next step before the time specified has elapsed, the execution of the L action will stop. SL (Set Limit) When a step is activated, the SL action associated with the step is executed. If the SL action has been executed for a certain amount of time before control is passed to the next step, the execution of the SL action will stop automatically, and the system will execute a final scan. If the control is passed to the next step before the time specified has elapsed, the execution of the SL action will stop after the time specified has elapsed. considered. When STEP_1 is activated, Action1 and Action2 are executed.
There are two situations which need to be (a) STEP_1 is activated for more than two seconds. After Action1 and Action2 have been executed for two seconds, the execution of Action1 and the execution of Action2 will stop, and the system will execute final scans. (b) STEP_1 is activated for less than two seconds. After control is passed to the next step, the execution of Action1 will stop, and the system will execute a final scan. The execution of Action2 will stop after two seconds have elapsed. R (Reset) When a step is activated, the R action related to the step is not executed, and the system executes a final scan.
An action qualified by S, SD, DS, or SL will not be executed if it is qualified by R. 14-17