# Circuit converts 2 wire output to 2 pair

Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=139097
Printed Date: December 06, 2021 at 5:41 AM

Topic: Circuit converts 2 wire output to 2 pair

Posted By: old mullett
Subject: Circuit converts 2 wire output to 2 pair
Date Posted: June 17, 2015 at 11:23 AM

I have a single pair output that "sends" two signals. One is a solid 12vdc output and the other is a pulsing 12vdc output. Each is for a different occurrence. I need this output to be separated into two (2) separate outputs (can be dry relays or solid 12vdc). System currently designed to operate an alarm with solid tone for one function and pulsed for another function. I want to retransmit each separately as each may occur at different times. Thank you in advance for any input.

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A wet bird never flies backward at night.

Replies:

Posted By: hotwaterwizard
Date Posted: June 17, 2015 at 8:26 PM
Do you want the output of each to follow the pattern of each output?
Or do you want the output to just trigger different steady output latching relays? Or do you want each to last just the same duration as each pulse with a steady output?
I think I just confused myself.

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Posted By: old mullett
Date Posted: June 18, 2015 at 1:59 PM
Most alarms have two or more sensor inputs. When any one is triggered, it sets off a siren via a one pair output. If a different type of alarm is triggered, there can be a second one pair output to allow a different type signal to activate. In my case, the two inputs use the same pair of wires BUT the system electronically causes a solid 12vdc OR a pulsing 12vdc output for audible identification of each input. What I need is a device that can sense the solid output vs the pulsing output and activate dry contacts for each separately. (i.e. solid goes to dry contact 1, pulsing goes to dry contact 2).
Many alarm systems use one pair out as they use single tone buzzers (that can sound solid or pulsed). Many retransmit devices require a separate closure to activate each different channel of that device.

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A wet bird never flies backward at night.

Posted By: hotwaterwizard
Date Posted: June 18, 2015 at 9:20 PM
Okay? We will need some kind of circuit that can detect square wave from steady voltage and trigger a relay to put out a continuous voltage for each one during the duration of the signal and go off when it is deactivated.? Is this correct?

Edge Triggered Latches and Flip Flops

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Posted By: old mullett
Date Posted: June 20, 2015 at 11:39 PM
The output of the system is a result of either of two sensors being "tripped". The Control Panel converts the input into 12vdc output at the 2 wire output. In order to distinguish which sensor has been tripped, the control sends out either 12vdc continuous OR 12vdc in 1/2 second pulses. A sounder device (such as a car horn) will then be an audible signal (by sound) which sensor has been tripped.
This concept is good unless the output needs to be used for other devices; ones that need a separate dry closure OR a separate solid voltage for each sensor trip A or B. For instance a dialer that will notify via telephone whether an interior break in or an engine break in has been alerted. This takes two different inputs to the dialer circuitry (dry closure OR continuous 12vdc). I have made drawings but do not know how to post them on this site.
Thank you for your help so far.

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A wet bird never flies backward at night.

Posted By: hotwaterwizard
Date Posted: June 22, 2015 at 9:12 PM

It may be less complicated to buy an alarm that does what you need.

A complicated circuit can be made to differentiate between the two signals but, the cost and time will excede the cost of a different alarm system.

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Posted By: old mullett
Date Posted: June 22, 2015 at 9:41 PM
Amazing but that was the realization I came to. Hopefully there is a manufacturer still out there that makes one. So far I have not found one.
Thank you for taking time to run through that with me. Have a great day.
M.

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A wet bird never flies backward at night.

Posted By: denton92
Date Posted: July 14, 2015 at 4:44 PM
You can look for a circuit that detects different voltage level, or a certain level of voltage. Now you will be working with RMS or effective voltage values. When the signal is solid 12 volts DC then the circuit that detects the 12 volts DC will trigger. And for the pulsating 12 volts DC signal, you will need another circuit that will detect 6 volts DC, the RMS or effective value of a pulsating 12 volts DC signal.

Regards,
Denton P.

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