Simple Ladder Pulse

This morning I had someone send a ladder diagram on a dry-erase board with an attempt at creating a 10 second pulse to dispense something. It was much more complex than it needed to be and I tried to explain verbally how to do it. I was at home using my phone and realized I didn’t have any way to draw a diagram, so I decided to post it here.

Pulse with On-Delay Timer

I am using CodeSYS to show this, so it looks different than it would in Allen-Bradley or Siemens, my typical platforms. The drawings that were shown to be used several M0.x bits, but also used the abbreviation “DN” for the timer, so it could have been about anything. The R-TRIG here is a one shot, abbreviated ONS for Allen-Bradley, FP for Siemens, DIFU for Omron, PLS for Mitsubishi… it is important in this case in the event of the Device tag staying on too long.

Pulse with Off-Delay Timer

This is another fun way to create a pulse with a TOF. Remember that an Off-Delay Timer is done immediately, and starts timing when the power turns OFF. For Allen-Bradley, the Pulse can not be in the same rung as the timer, since the one-shot would prevent power to the coil. With Siemens, the Pulse Driver contact could be replaced with the Pulse coil.

Every platform is different, so you need to test this on your own platform. It truly is pretty simple though.


Electrical Engineer and business owner from the Nashville, Tennessee area. I also play music, Chess and Go.