Chapter 14 Sequential Function Chart If users want to edit a sequential function chart, they have to create actions, assign the actions to the steps, and assign qualifiers to the actions. The Action Settings window and the corresponding action list are shown below. Final scans are important procedures during the execution of a sequential function chart. After the execution of an action stops, the system will automatically execute a procedure to disable all the outputs in the action.
If a final scan is executed, the coils driven by the instruction OUT will be OFF, the application instructions and the function blocks will not executed, the timers will be reset, the states of the coils driven by the instruction SET or RESET will remain unchanged, the counters will stop counting, the states of the contacts of the counters will remain unchanged, and the values in the counters will remain unchanged. Action0 in the figure below is an action associated with STEP_0, and is an N action. When STEP_0 is deactivated and STEP_1 is activated, the system executes a final scan. 14-5