29.3 Generating a Pulse at One Second Intervals

Logic Program

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).

Function Summary

The basic operation of the timer instruction (TON) is to repeatedly turn on Timer variable.Q after the defined time has elapsed.

  1. After 1 second (1000 ms), the TON command Clock1SecondPulse.Q turns on.

  2. Upon the next scan, the TON command will be reset after the normally closed contact turns on.

  3. 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 the next scan.
32. Logic Instruction List