light switch

[gihlutax]

Hello,

I am stuck with a light switch.

I want to light two lamps with two different switches.
And I want to switch 1 lamp apart from those two.

I0.0 and I0.1 operate q0.0 and q0.1, that's no problem,I already have that.
But switch i0.2 must operate q0.1 apart, and i0.0 and i0.1 have a higher priority.

So if I turn on q0.0 and q0.1 with i0.0, and I turn off q0.1 with i0.2, lamp q0.0 continues to burn. But if I press on i0.0 to turn off q0.0, then q0.1 turns on back.That may not, he must remain off.

Hopefully someone can help me
Thanks

 

[pwrengrds]

buy an Ugly's Electrical References book on how to wire switches and learn the ways of the electrician.

 

[Skogsgurra]

Seems like a simple task. But your specification is not very clear.

Are your inputs supposed to toggle the lamps on/off or are they supposed to be static on/off? The "switch i0.2 must operate q0.1 apart, and i0.0 and i0.1 have a higher priority" part of the specification indicates that io.0 and io.1 are static.

It would also help to know if io.2 toggles or is static. You will have two very different diagrams depending on what the case is.

Gunnar Englund

http://www.gke.org

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[gihlutax]

I0.0,I0.1 and I0.2 are monostable pushbuttons, when I stop pressing on the button de switch opens.

So I used a set-reset function to operate q0.0 and q0.1 With I0.0 and I0.1

 

[Skogsgurra]

OK. Will have a look at it. Vous êtes Francais?

Gunnar Englund

http://www.gke.org

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[gihlutax]

no I'm belgian, yes my english is not perfect

 

[Skogsgurra]

Like my French. But I thought I saw quelques influences Francais.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[Skogsgurra]

If I understand you right, you toggle a latch on/off with io.0 and another latch with io.1. OK so far.

Then, you want a third input, io.2, to override the io.0 so it will be possible to switch the lamp on/off from io.2, but 10.0 shall have priority over io.2?

I am not so sure if that specification is consistent. It will not be possible to let a momentary signal have priority over another momentary switch if you want to use the second switch to override the first switch.

I may have misunderstood you. But that is how I interpret your description.

What PLC are you using? Are you using laqdder, logic diagram or statement list?

Gunnar Englund

http://www.gke.org

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[gihlutax]

Thank you for your fast reply's

That's what I want like you just explained,
normally it's possible, someone said I have to use "positive and negative edges".

Tommorow I will try to find a solution, now I can't try, cause the plc is not mine.

I'm using S7 and ladder with microwin step7.

 

[Skogsgurra]

Yes, you shall use the edge detector FB, aka monoflop, to set/reset the latch. But that will not make it possible to override input 0 AND at the same time let it be dominant over input 2.

It is possible that you need to reconsider the momentary action of inputs 0 and 1 and use edge detection on input 2. But I still have a problem seeing how input 0 can be dominant BOTH ON AND OFF. You may have to chose one of those states to be dominant.

Or, you have to employ some mind-reading techniques in the S7

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[gihlutax]

I've finaly found it.

For those who are interested in the attachment you can find the circuit in ladder (pdf format).

@Skogsgurra thanks a lot for your help.