ISPSoft User Manual

Chapter 12 Sequential Function Chart
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.
STEP_0 in the figure below is activated. M10 in Action0 is ON, and therefore M0 is ON, M1 is set to
ON, M2 is reset to OFF, the value in T0 is 30, and the value in C0 is 5.
STEP_1 in the figure below is activated. Although M10 is ON, M0
is OFF, and T0 is reset. The state
of M1, the state of M2, and the value in C0 remain unchanged.
12-5