In the following example logic program, there is a normally
closed contact set to "Timer variable.Q" and a timer instruction
set to 1 second (1000 ms).
The basic operation of the timer instruction (TON) is to
repeatedly turn on "Timer variable.Q" after the defined time has
elapsed.
After 1 second (1000ms), the TON command
"Clock1SecondPulse.Q" turns on.
Upon the next scan, the TON command will be reset
after the normally closed contact turns on.
When TON command is reset, the normally closed
contact will be turned off and the TON command will return to a
conducting state.
As a result, the normally closed contact "Clock1SecondPulse.Q"
repeatedly turns OFF for one second and turns ON upon the next
scan. Chapter 31 Logic
Instruction List