Stumped on Ladder Diagram


Thread Starter


I am a last term Electronics Engineering Technician , and I am stumped on a Ladder diagram I have to build for a PLC lab, I wouldn't be putting a message out if I wasn't stuck, any help would be very appreciated.

The process is as follows: a box is placed on a conveyor, it is set on LS1 and that activates the conveyor motor, the box leaves LS1 and hits LS2 at which a spray gun paints the box, not when the box passes LS3 its stops painting and reverses, now the problem is that LS3 is normally open (NO) and the spray gun turns off when it is closed and re-opened.

I can email the lab to anyone that will be so kind to assist me.


Hum, let's see. You want to turn off the paint and reverse the conveyor after LS3 has made, and then cleared.

You might think about latching a bit on the rising edge of the LS3 signal, and on the falling edge signal of LS3.

Send me a little more info if you can. I'm not working on anything today, I'd be glad to help.

[email protected]

Steve McAlpin

Ya if you want me to take a stab at it I'm willing, from you description the box is places on ls1 which starts the motor and moves the box when it hits ls2 a paint sprayer is activated and continues to paint until it hits ls3 at that time the box reverses to be painted again what happens
then does it go all the way back to ls1 for removal? Let me know and I'll give it a shot.

Steve McAlpin
Control System Supervisor
Calleguas Municipal Water District
2100 Olsen Road, Thousand Oaks, CA 91360
Phone: (805) 579-7148 fax: (805) 579-3721
Cell Phone: (805) 501-9037
E-mail: [email protected]
If you don't already have a solution, please forward the lab and I would be glad to help. I just don't know how complex the solution will be forced to be by what's available in the lab.

<sull[email protected]>