hello,

Tinkerer here. I’m using 24vdc to an input on my PLC to turn on a Servo which is currently being handled by a toggle switch.

I could just use the toggle switch to complete this But I’d like to use two momentary push buttons to handle this action; I think it looks nicer. A start(NO)and stop(NC)if you will, is a DPST relay a good option to handle this?

 

Here's a DPST relay configured to latch on and off using two push-buttons.

 

Here's a DPST relay configured to latch on and off using two push-buttons.

View attachment 151763

Thanks I feel like a fool it looks so simple now that you’ve literally drawn it out for me.

Does it matter if it’s dpst or dpdt? The dpdt will just have two unused spots correct?

 

Why are you using external hard wired logic on a PLC?
What make of PLC?
Max.

 

Thanks I feel like a fool it looks so simple now that you’ve literally drawn it out for me.

Does it matter if it’s dpst or dpdt? The dpdt will just have two unused spots correct?

Correct.
It can be either DPST or DPDT.

 

The only reason I can see of not doing it internally is that there is no access to a programmer!
Max.

 

The only reason I can see of not doing it internally is that there is no access to a programmer!
Max.

What do you mean max?

 

What do you mean max?

Sorry I just read your previous post it hadn’t updated it


The plc is an Omron cp1h and I have an external port next to these push buttons ran for easy hookup.

 

Not really sure of your meaning, Which external port are you using or referring to?
Max.

 

I think I may have split your questions and answer up max

You said there would be no access to the programmer- I have a external port ran from the PLC to the outside of my little control panel which is Where I plan to put these momentary start/stop buttons. Once on and relay is in on state and the allotted time is met ( set by plc ) to the the servo get to up speed my little machine will enter a run state.

As for why I’m using hard wired logic: I just thought it would be an ok idea to have it do a simple check to the plc that “Hey the start button was hit and relay is on, user is clear go ahead and run”. And it will continue to run until I hit the stop button and relay is de energized.

 

What I meant was that that I understood you presently had a toggle switch into the PLC which in turn controlled the servo. Not sure why you would use a toggle switch into a PLC if this is the set up.
It is a little vague as to the present set up, but if there were spare inputs to the PLC, all the logic could be done by internal logic.
Max.

 

What I meant was that that I understood you presently had a toggle switch into the PLC which in turn controlled the servo. Not sure why you would use a toggle switch into a PLC if this is the set up.
It is a little vague as to the present set up, but if there were spare inputs to the PLC, all the logic could be done by internal logic.
Max.

Ahh
The first toggle switch was really to make sure my “continuous run condition could of been met” which will now be handled by the relay

I’m not sure if there will be spare inputs. Presently yes;but if I could save an input I’m going to do so as I’m I using a lot of pneumatics with sensors and I may need more. Since this is all introductory to me I may not be doing it the most efficient way But I believe it will satisfy my needs.

 

Correct.
It can be either DPST or DPDT.

I’ve found an 8501kpdr12v53

Gonna hook this up after a beer!

 

Sometimes you have do do things when conditions demand, but if not already aware, is to remember if you want to simulate a two posn toggle switch using a single input to a PLC is a single contact maintained P.B. or a simple on/off toggle.
Max.

 

Sometimes you have do do things when conditions demand, but if not already aware, is to remember if you want to simulate a two posn toggle switch using a single input to a PLC is a single contact maintained P.B.
Max.

Nope absolutely a maintenance on off PB would’ve sufficed! But I did want two buttons one for start and one for stop. And this setup for this relay will be good knowledge moving forward for future projects who knows maybe I’ll just take the easy maintained PB route. But I do like the look of it. If I can get the code right for the plc. The “stop button” might also be a (runout / finish cycle then stop) But that is down the road.

The relay I found is NC/NC so I may not get to do it today might have to dig around or order one


Thank for the input Max

 

So is the motor or the external relay controlled by the PLC at present?
Max..

 

So is the motor or the external relay controlled by the PLC at present?
Max..

At present the motor is controlled by the PLC



Relay is just going to be the 24v input to PLC for on/off

 

Well if there is no alternative, but to me, it seems a shame to have a PLC available and end up with hardwired logic.
Max.

 

The relay I found is NC/NC

What is an NC/NC relay?
The 8501kpdr12v53 relay is DPDT.

 

What is an NC/NC relay?
The 8501kpdr12v53 relay is DPDT.

Yep sorry, got excited. I found a wiring diagram for it online
My outer casing was broke I should be able to wire it up and test it out sometime tonight. And then I’ll have my on/off buttons

Thank you