Volt Free Contact

sparky64 · May 7, 2003

Might sound like a daft question but.......

We have contractors on site installing some alarm monitoring equipment for boilers, pumps, fans etc.

I've asked them for some digital signals for our plc to monitor and bring on our panelview alarms...etc.

They told me that they would give me an ammount of volt free contacts.

My understanding of this, is that they will use the alarm signals they generate, to energise relays, and i can switch our 24 VDC through their relay contact to give me an inut to our plc, but a colleague is disagreeing with my understanding of this terminology.

He says that no voltage is present at any time on the contact hence "volt free", if this is correct, how can i get my 24VDC signals.

Could someone clarify this for me please.

Cheers
Sparky

Goody · May 7, 2003

This has been debated before, and your way is the correct thinking.

Volt free contacts are for the customer to use for his own signals.

How could they do anything if they remained 'volt free'. They might as well not exist.

They are volt free when the installer finishes the job. You then put your signal voltage through them.

sparky64 · May 7, 2003

Thanks for the reply goody

Looking forward to going back to work tomorrow, my colleague thinks he invented controls....he's a right smart ***.

I found another debate on "Volt Free Contacts" at http://www.control.com/1026171624/index_html
If anyone is interested.

Cheers
Sparky

thunda · May 7, 2003

I'd have to agree I think his idea of "at anytime" ends when he is done the job.

Rick Densing · May 7, 2003

Volt free is exactly as you thought you understood it. I have heard the term "dry contact" and "potential-free contact" to describe the same.

Of course, this is assuming that is what the contractor thinks it means.

Steve Bailey · May 7, 2003

When you get to work tomorrow, ask your colleague if he has a metric pipe wrench that you could borrow.

93lt1 · May 7, 2003

Steve Bailey said:
When you get to work tomorrow, ask your colleague if he has a metric pipe wrench that you could borrow.

Or a left handed screwdriver.

Rick Densing · May 7, 2003

I once convinced a guy that there was such a thing as 3 phase DC.

Tom Jenkins · May 7, 2003

My favorite is the "enngineer" that believed it when the technician told him the system failure was the result of electron spin out on wire bends that were too short.

Here is the thread on this site - I hope it doesn't cause more confusion.
http://www.plctalk.net/qanda/showthread.php?s=&threadid=2074&highlight=dry+contact

john paley · May 7, 2003

Once we were missing a phase and sent an Engineer to the Store room for a "Box of Phases" and a tube of frequency grease. He went for it.

bob1371 · May 7, 2003

I guess all places have one of THOSE guys.
goto this link, I made a tribute to the one I work with.
http://www.angelfire.com/ego/mikescousin/index.html
his name is Mike and it hasnt done it, His cousin has.

enjoy

bob

rdrast · May 7, 2003

Steve Bailey said:
When you get to work tomorrow, ask your colleague if he has a metric pipe wrench that you could borrow.

I don't have a pipe wrench, but I actually **DO** have a metric adjustable wrench... the jaw carriage is marked with gradients in millimeters.

You want more fun? Soak a roll of paper towels with scoth-guard, let them dry out, and put them in the rest rooms.

Eric Nelson · May 7, 2003

More "Special" Wrenches...

I have a what you'd call a "left-handed" adjustable wrench. The thread is reversed, so when you rotate it 'the normal way' to open the jaw, it closes. IOW, it works backwards. Here's a picture:
[attachment]
Notice the "MADE IN USSR" stamp on the handle. Are left-handers more prevalent over there?...

beerchug

-Eric

kamenges · May 7, 2003

We once had a purchaser yelling at one of our suppliers wondering where our roll of Fallopian tube was. That was kind of entertaining.

93lt1 · May 7, 2003

Well Steve......

Look at what you started! utoh

Volt Free Contact

sparky64

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Goody

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sparky64

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thunda

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Rick Densing

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Steve Bailey

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93lt1

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Rick Densing

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Tom Jenkins

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john paley

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bob1371

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rdrast

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Eric Nelson

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kamenges

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93lt1

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