Schematics question

Hi, I am reading instrutions on hooking up an Intellibeam IB-250s intruder alarm system.. It sends a beam from transmitter to reciever and if broken
sets alarm off. I see in the diagram it has 3 wires going from the reciever to the alarm.. It says: Output Alarm, then three lines with one appearing to be a switch from the middle line going to the third line(it is touching the third line)..each line/wire is labelled: N.O. COM and N.C. I have a simple bell alarm or whistle alarm which only have two wires coming off. What is the third wire for? Thanks req
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
reqluq wrote:

COM is common, NO is Normally Open, and NC is Normally Closed, these are the contacts of the relay that controls the output. The connection between COM and NO closes when activated, while the that between COM and NC opens when activated.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thanks for the response. how do I connect those three wires to the two wire bell, if that is the way to do it.. the alarm has positve and negative wires only. Layman here req
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
reqluq wrote:

Those contacts are just a switch, it sounds like you need a separate power source for your alarm. You would wire the N.O. and COM terminals just as you'd wire a switch in series with power to the alarm. When the relay is triggered, the contacts close and it completes the circuit.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I really apprecite you taking the time out to answer my query...so where do the three lines go if I do get a separate source...the question is where do the three lines go thanks req
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 3/10/2010 12:30 AM, reqluq wrote:

You only use two of the lines. Usually the contact state of a device like this is determined while the unit is powered off. However, I've seen devices that change their state after being powered on. So, with this being stated, you will make a connection to the line labeled COM. Next you will make a connection to either the NC, or, the NO line, but not both. If the contact state of the device does not change after being powered up you will make connections to the COM line and to the NO line, leaving the NC line *NOT CONNECTED*. If the device changes the contact state after powering up, then you will make connections to the COM line and the NC line. The second option will not work in an installation that is not part of a system that separates the device power and the "device state" power.
Are you using this device as part of a complete system, or as a stand alone DIY project?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Stand alone req
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Depends on whether you want the alarm to sound when the relay closes or the relay opens. Like I said, it's a switch, one input and two mutually exclusive outputs. Imagine a valve that can direct water from one input (COM) to either of two outputs. Hook it up and see what happens, if the alarm sounds when you want it quiet and is quiet when you want it to sound, change to the other contact.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
James Sweet wrote:

The relays are low voltage, low current and intended to be connected to an alarm panel.
--
Greed is the root of all eBay.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I want the alarm to sound when someone breaks the beam. layman here. req
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 3/11/2010 1:33 PM, reqluq wrote:

Do you have a DC power supply and some wire for the photo sensor?
How about a Continuity tester (Ohm meter)?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 10/03/2010 22:19, [SMF] wrote:

"Continuity tester" "DC power supply" "mutually exclusive outputs" "Ohm"
layman whoosh, ye need to dumb down folks!
--
Adrian C

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 3/11/2010 6:24 PM, Adrian C wrote:

Would doohickey and thingamajig suffice?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Adrian C wrote:

Not sure if that's sarcasm or not, but this *is* an engineering group. There are plenty of other forums and websites for more basic information. You wouldn't call up a master carpenter to ask how to nail two boards together and then ask what a hammer is.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I'm not asking what a *hammer* is.. my question is not that remedial thanks req
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/03/2010 06:46, reqluq wrote:

http://www.howstuffworks.com/electricity3.htm
--
Adrian C

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Judging by the situation as described, where the photocell is active when the beam is present, it will be holding the relay open when energized and letting it close when the beam is broken- this would mean that the alarm should be fed, from it's power supply, through the NC and common leads. Since there may be some electronics present to change this, the simple solution is to take any pair, common + NC or common+ NO and try it. If it doesn't work as desired, when the beam is broken, try the other pair. It's an either/or situation.
--
-----
Don Kelly
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

My question is not on how electricity works. It's about reading a schematic and how to follow it You should have sent me this: http://www.learn-c.com/schemat.htm
or this: http://www.tpub.com/content/doe/h1016v1/css/h1016v1_110.htm
req
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 3/15/2010 11:38 PM, reqluq wrote:

Hehe, that wasn't exactly how you presented your question. :)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Not THAT much of a layman :-) req
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.