# X-Ray in use sign



## MDShunk (Jan 7, 2007)

I've got to go look at a little thing on Monday where I'll be asked to wire an "X-Ray In Use" sign outside an X-ray room. 

What typically turns these things on? A relay in the X-ray equipment? Wall switch? Door switch on the entry door? Something else?

I want to seem somewhat like I know what I'm doing when I get there.


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## cdnelectrician (Mar 14, 2008)

MDShunk said:


> I've got to go look at a little thing on Monday where I'll be asked to wire an "X-Ray In Use" sign outside an X-ray room.
> 
> What typically turns these things on? A relay in the X-ray equipment? Wall switch? Door switch on the entry door? Something else?
> 
> I want to seem somewhat like I know what I'm doing when I get there.


I was actually talking to a guy at work about something similar last week. All he ever does is hospitals and he mentioned it being part of the machine itself. I can ask him on Monday but that might not help you much.


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## mikeh32 (Feb 16, 2009)

the light is activated when the main power to the xray is turned on...

I actually asked an xray tech this. i kinda shattered my leg and had a couple hundred xrays


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## leland (Dec 28, 2007)

MDShunk said:


> I've got to go look at a little thing on Monday where I'll be asked to wire an "X-Ray In Use" sign outside an X-ray room.
> 
> What typically turns these things on? A relay in the X-ray equipment? Wall switch? Door switch on the entry door? Something else?
> 
> I want to seem somewhat like I know what I'm doing when I get there.



WOW !!!!!!!!!!!!!!!

I'm gonna save this post !!!!!!!!!!!!!!!! ()

Typically there is a contact inside the equipment for this purpose.
Similar to laser labs.
some times there will be a door switch interlock as well.So equipment cannot be used until the room is secure.


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## George Stolz (Jan 22, 2009)

I've actually lent a hand in two of these, and I'll be dipped if I can remember. 

IIRC, there are contacts inside the machine to drive a relay that you provide, to turn on/off any lights you desire, including the x-ray in use sign.

It's coming back, I think I actually have a picture, stand by.

Edit: No meaningful picture, but that's right.


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## bav_21 (Nov 27, 2009)

*Relay*

George is right I have done 2 as well


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## goose134 (Nov 12, 2007)

I've only done two machines (Caremark), but they had a 120 volt circuit activated by the equipment. A 1/2" pipe to the cable tray should do it. There was a door interlock system, but it didn't have any connection to the light.


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## randomkiller (Sep 28, 2007)

GE machines have a relay in their equipment as well.


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## mattsilkwood (Sep 21, 2008)

All the ones Ive worked on have a set of dry contacs.


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## wojomato (Sep 24, 2010)

*dry contacts*

There is usually a set of dry contacts in the x-ray generator that closes when x-ray is on. These contacts are rated at 24 volts so a stepdown transformer and 24v relay is supplied by the electrician. Configuration is as follows: 120 volts ac coming into stepdown transformer and to 24v relay n.o. contacts. The 24vac from secondary of transformer goes to dry contacts in the x-ray generator and back to 24v relay coil when x-ray is on. 24v relay closes supplying 120vac to light sign.


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## MDShunk (Jan 7, 2007)

wojomato said:


> There is usually a set of dry contacts in the x-ray generator that closes when x-ray is on. These contacts are rated at 24 volts so a stepdown transformer and 24v relay is supplied by the electrician. Configuration is as follows: 120 volts ac coming into stepdown transformer and to 24v relay n.o. contacts. The 24vac from secondary of transformer goes to dry contacts in the x-ray generator and back to 24v relay coil when x-ray is on. 24v relay closes supplying 120vac to light sign.


Oh, so that's how you wire up one of 'dem dare relay thingies. :laughing::laughing:

The job is long done, and I used an RIB.


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## wojomato (Sep 24, 2010)

MDShunk said:


> I've got to go look at a little thing on Monday where I'll be asked to wire an "X-Ray In Use" sign outside an X-ray room.
> 
> What typically turns these things on? A relay in the X-ray equipment? Wall switch? Door switch on the entry door? Something else?
> 
> I want to seem somewhat like I know what I'm doing when I get there.


 
Just thought I'd add some knowledge for future generations.


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## RIVETER (Sep 26, 2009)

MDShunk said:


> I've got to go look at a little thing on Monday where I'll be asked to wire an "X-Ray In Use" sign outside an X-ray room.
> 
> What typically turns these things on? A relay in the X-ray equipment? Wall switch? Door switch on the entry door? Something else?
> 
> I want to seem somewhat like I know what I'm doing when I get there.


I'll be wrong, of course, but I think it should be a manual switch to control the situation.If it is a contact in the machine that does it, and you are relying on it, a person could... on the threshold of the SHOT... come in the door.


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## MDShunk (Jan 7, 2007)

RIVETER said:


> I'll be wrong, of course, but I think it should be a manual switch to control the situation.If it is a contact in the machine that does it, and you are relying on it, a person could... on the threshold of the SHOT... come in the door.


Like I say, the job is long done. There were a set of dry contacts in the machine for this purpose, and the sign was inspected by my state's Department of Environmental Protection to come on with the machine automatically. Above a certain x-ray output (which this machine did not reach), the door needs a door switch to interlock with the machine also. The terminal strip did have a jumper where such a door switch contact would go, should I have chosen to wire it in.


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## RIVETER (Sep 26, 2009)

MDShunk said:


> Like I say, the job is long done. There were a set of dry contacts in the machine for this purpose, and the sign was inspected by my state's Department of Environmental Protection to come on with the machine automatically. Above a certain x-ray output (which this machine did not reach), the door needs a door switch to interlock with the machine also. The terminal strip did have a jumper where such a door switch contact would go, should I have chosen to wire it in.


I am pretty smart, but I will ask you what the definition of "dry" contacts is,,,now I feel pretty dumb...don't tell anybody I asked, but I am serious.


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## MDShunk (Jan 7, 2007)

RIVETER said:


> I am pretty smart, but I will ask you what the definition of "dry" contacts is,,,now I feel pretty dumb...don't tell anybody I asked, but I am serious.


Unpowered. Just two terminals that make.

A wetted contact would be a mercury contact.


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## RIVETER (Sep 26, 2009)

MDShunk said:


> Unpowered. Just two terminals that make.
> 
> A wetted contact would be a mercury contact.


I still feel dumb....


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## MDShunk (Jan 7, 2007)

RIVETER said:


> I still feel dumb....


Can't fight nature. :jester:


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## RIVETER (Sep 26, 2009)

MDShunk said:


> Can't fight nature. :jester:


Yeah, it's in the genes. Im just tryin'.


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## Jlarson (Jun 28, 2009)

MDShunk said:


> Unpowered. Just two terminals that make.
> 
> A wetted contact would be a mercury contact.


Some people use wetted to mean contacts that supply voltage in my experience.


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## RIVETER (Sep 26, 2009)

Okay, Md, here we go. I honestly don't know what a dry...or wet contact is. How did that terminology come about?


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## TOOL_5150 (Aug 27, 2007)

RIVETER said:


> Okay, Md, here we go. I honestly don't know what a dry...or wet contact is. How did that terminology come about?


A dry contact - has to be used with another relay to make and break the load.

~Matt


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## Jlarson (Jun 28, 2009)

RIVETER said:


> Okay, Md, here we go. I honestly don't know what a dry...or wet contact is. How did that terminology come about?


I want to say they came from the telecommunication industry for some reason.


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## RIVETER (Sep 26, 2009)

Jlarson said:


> I want to say they came from the telecommunication industry for some reason.


And the answer is???


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## Jlarson (Jun 28, 2009)

RIVETER said:


> And the answer is???


I have seen them used like this, both by others and in instructions. 
I don't think there is a real standard but I could be wrong.

wet- mercury 
dry - no mercury 

and 

wet - voltage provided
dry - no voltage provided


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## MDShunk (Jan 7, 2007)

RIVETER said:


> Okay, Md, here we go. I honestly don't know what a dry...or wet contact is. How did that terminology come about?


I think it involved two guys in the 1930's from the Stromberg-Carlson company and a great many pints of Guinness. Or, I could be totally making that up.


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## wojomato (Sep 24, 2010)

RIVETER said:


> I'll be wrong, of course, but I think it should be a manual switch to control the situation.If it is a contact in the machine that does it, and you are relying on it, a person could... on the threshold of the SHOT... come in the door.


 Most X-Ray rooms have an optional door switch that terminates the x-ray exposure when the door is opened. The x-ray in use light is supposed to be a warning not to open the door when x-ray is on. Many times the customer will opt not to have a door switch, typically in trauma rooms where they don't want to have to restart the procedure because emergency personnel open the door.


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## wojomato (Sep 24, 2010)

RIVETER said:


> And the answer is???


 A dry contact is a set of 2 switch contacts, like a set of contacts from a relay or from a toggle switch, etc, that has both terminals available and neither contact is connected to power or anything else. ("Dry" = no "juice").

So, you can hook up the contacts to anything you want, not worrying if they are already connected to power or any other circuit.


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## high leg (Feb 2, 2008)

All I do is hospitals in Fl.. You control power will come off of the X-Ray "head" unit. Yet, the light will only come on when the door is closed. Meaning a limit switch installed on the door will be your dry contact point.


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## LARMGUY (Aug 22, 2010)

high leg said:


> All I do is hospitals in Fl.. You control power will come off of the X-Ray "head" unit. Yet, the light will only come on when the door is closed. Meaning a limit switch installed on the door will be your dry contact point.


I know it's an old post but, limit switch? Why not just a plain old magnetic door contact? $.75 and 10 minutes compared to $10. and up.


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## George Stolz (Jan 22, 2009)

Marc, when you get around to doing that X-Ray thingy, gimme a call and I'll walk you through it. When you get to it.


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## Wirenuting (Sep 12, 2010)

And on a side note,, if it's an older Hospital 
Be careful of lead lined walls. 
I walked in on some co-workers drilling thru the wall in a Dr's X-ray reading room. It was an old X-ray room from years ago. The fine lead dust was all over the films. 
Alot of ladies had to hear that they needed biopsies because of it. 
It was just luck that I caught it by walking by and my boss thought I was nuts for stopping the job. 
They result was a lot of Mamo x-ray retakes and no Biopsies. 
I spent 8 years as head electrician there and it was what gave me ulcers.


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## steelersman (Mar 15, 2009)

MDShunk said:


> Unpowered. Just two terminals that make.
> 
> A wetted contact would be a mercury contact.


A wet contact would have it's own voltage on it from it's own power source such as is present in speed drives for the enable, or start or safety loops.


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## MDShunk (Jan 7, 2007)

steelersman said:


> A wet contact would have it's own voltage on it from it's own power source such as is present in speed drives for the enable, or start or safety loops.


Two different things, and both are correct. Depends on the context in which they are being used. A wetted contact can mean (physically) wet with mercury, or having an (electrical) wetting voltage present on them. 

In your example, you don't really accurately describe a wet contact, however. What you describe is more accurately an "output". A true wet contact is a contact for AC that would otherwise be a dry contact, but the equipment will add a DC wetting current to the relay contacts. I'm not sure at what point in time (PLC age, I think) "wet contacts" suddenly meant relay outputs in which voltage was supplied, but it's technically incorrect. Enough people have been using it incorrectly for that purpose that it's almost now a third and also correct version of wet contact.


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## BuzzKill (Oct 27, 2008)

MDShunk said:


> I've got to go look at a little thing on Monday where I'll be asked to wire an "X-Ray In Use" sign outside an X-ray room.
> 
> What typically turns these things on? A relay in the X-ray equipment? Wall switch? Door switch on the entry door? Something else?
> 
> I want to seem somewhat like I know what I'm doing when I get there.


You said it best awhile ago that when a customer called and asked if you can do "this or that type" of work, you'd respond, "Oh yeah, sure." Time to wing it!


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## BuzzKill (Oct 27, 2008)

MDShunk said:


> I've got to go look at a little thing on Monday where I'll be asked to wire an "X-Ray In Use" sign outside an X-ray room.
> 
> What typically turns these things on? A relay in the X-ray equipment? Wall switch? Door switch on the entry door? Something else?
> 
> I want to seem somewhat like I know what I'm doing when I get there.


It's got to be a signal to the sign from the equipment, possibly LV, just reverse engineer the damn thing.


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## MDShunk (Jan 7, 2007)

This post was started back in April for a little job that was going to happen a few days later. It's long since been done.


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## BuzzKill (Oct 27, 2008)

well...how'd it turn out?


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## BBQ (Nov 16, 2010)

BuzzKill said:


> well...how'd it turn out?



Not so well ....


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## TOOL_5150 (Aug 27, 2007)

so, this thread is officially dildos.


~Matt


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## BBQ (Nov 16, 2010)

Wirenuting said:


> And on a side note,, if it's an older Hospital
> Be careful of lead lined walls.


New x-ray rooms will have lead lined walls as well.



> I walked in on some co-workers drilling thru the wall in a Dr's X-ray reading room. It was an old X-ray room from years ago. The fine lead dust was all over the films.
> 
> Alot of ladies had to hear that they needed biopsies because of it.


Why?




> It was just luck that I caught it by walking by and my boss thought I was nuts for stopping the job.


I would have thought that as well.




> They result was a lot of Mamo x-ray retakes and no Biopsies.


Why would they have to do 'retakes'?


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## justinr (Aug 12, 2009)

"dry contact" = physical contact, like a relay contact. Anything else might be transistor driven, electronic. I've seen PLC output cards put out a voltage for whatever reason, and some solenoid valves NEED zero voltage to be completely de-energized.


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