Standard changer power failure alarm

[William]

I have 4 standard changers. I know that in the event of any type of error, the extra outlets on the power supply inside the machine go dead. I would like to install a relay or a sensor of some sort that interfaces with my alarm system so that the alarm calls me when the system has a problem. Has anyone tackled this problem and do you have any tips?

[MSKLAUNDRY.]

Go to radio shack and get a 110 volt AC relay,

http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F011%5F002%5F013%5F000&product%5Fid=275%2D217

Connect the coil leads of the relay to the AC outlet you wish to monitor. you may wish to fuse it also. 1/2 amp fuse would be fine. Depending on the alarm panel you use you will need the correct value EOL resistor (if used). Connect the relays common terminal to one side of the EOL resistor and the other side of the EOL resistor to the common side of the panel input terminal. Next take the normally open side of the relay and attach a wire to a unused zone of the alarm panel.

If the alarm panel is monitored by a central station you will have to reprogram the panel accordingly and also tell the central station how to respond in event of an alarm condition. Your alarm company should be able to handle that with no problem.

Note however that this setup will have no way of distinguishing from a power failure or a problem with the changer as all it is doing is monitoring the Ac outlet.

BTW EOL means End Of Line and is used to monitor the zone and is suppose to be installed at the last device on the zone.

[BWJR]

Marc,

That's amazing, do you also do brain surgery?

I'am impressed.

BWJR

[William]

Thanks Mark. Should the fuse be between the power and the relay or the relay and the alarm panel? Thanks!

[MSKLAUNDRY.]

Power and the relay coil.

[William]

Marc - I just want to make sure - the leads to the alarm panel should be on the normally open side of the relay. If they are on the closed side, they would send 120v to the alarm panel! So it is opposite what one would expect for an alarm sensor normally?

[MSKLAUNDRY.]

Let me clarify...

First you are going to identify the coil contacts of the relay you bought. Those two contacts are wires to the outlet of the change machine through the fuse of course.

Next identify the contacts "Common" and "N.O." on the relay. The common side of the relay contact will go to the common terminal of the alarm panel through the EOL resistor. Not knowing what panel you have I could not tell you what valve resistor to use. Napco panels use 2.2k ohm EOL resistors.

Next connect the N.O. contact of the relay to the unused zone line on the alarm panel.

As long as you do not wire it incorrectly there will not be any AC voltage going to the panel from the Changer.

BTW you can monitor all 4 changers in the same way but you will need 4 relays. You will just have to series the zone wires from each relay and only use 1 EOL resistor.

What is happening here is that when there is power to the outlet the relay will be energized and thus the N.O. contact of the relay will be closed. When either the changer goes into fault or there is a power failure the relay will deenergize and the contacts will open "N.O." and the alarm panel will sense an alarm condition and report that to the central station even if you have a power failure, provided of course that you have a battery installed in the alarm panel.