Design Help Needed - Alarm Ckt

Discussion in 'The Projects Forum' started by N2DFire, Apr 7, 2011.

  1. N2DFire

    Thread Starter New Member

    Apr 5, 2011
    Hello Everyone.

    I took on what I thought would be a simple job of cleaning up some (very) shoddy wiring / poor install work. This has since blossomed into a project that, while still with-in the scope of my technical abilities, has far exceeded my scope of design knowledge.

    Hopefully that's where you guys come in.

    "The Project"
    I am working on the temperature monitoring & alarming system on our recently constructed "Live Burn" fire training facility. It seems that the contractor who constructed the building sub'd all the electrical work over to a local contractor - which is all well and good until it came to the alarm system because they are NOT electronics contractors.

    In the photos below you can see some of what I have to work with.
    - Dayton 1EGJ1 Solid State Relay (3-32 VDC Input / 24-230 VAC 10A Output)
    - Federal Signal LP7 Sounder / Flasher (18-30 VDC 1.1A Surge 68mA average)
    - Telemecanique Switch (Model / Capacity as of yet undetermined)
    - Mean Well PLC-45-24 24VDC Power Supply

    What you can't see is the actual "Brains" of the system - a DAQPro 5300 portable data logger (7 Input points - 1 Output point).

    Also in my "parts bin" I have an older power supply (Mfg & model escape me right now) from which I can derive both a 5VDC and a 30VDC output. Both with sufficient amperage capacity for this project.

    The part that needs work
    O.K. - there are several issues here - the first being that the DAQPro's output point is a 5VDC 50mA MAX Load and the alarm circuit (as left) is 24VDC. So I need to create a 5VDC trigger circuit with a relay to trigger the alarm circuit. That I understand & can do (Plan to re-use the Dayton Relay here).

    However it's the actual Alarm Circuit that needs help.
    Right now the "Reset" switch is a N.C. push button that simply breaks the circuit to "silence" the alarm. Seeing as how this could be in "Alarm" for quite some time - it's not practical for someone to stand there and keep their finger on the button.

    What I'd like to have
    Assuming that the 5VDC trigger circuit from the DAQPro is active (i.e. in an Alarm State); for the alarm circuit - I would like to have it perform as follows:

    - A momentary switch that will "Silence" the audible / visual alerts and have them remain silent until the trigger circuit is no longer in an Alarm state.

    - A selector (toggle) switch that will choose to silence either Audible only or both Audible & Visual alarms on the LP-7 (For the moment please assume that the Audible & Visual aspects of the FS-LP7 can be separated. The documentation I have or can find on-line is not very clear on the subject)

    - A momentary switch that will "Reset" the system - meaning if the Audible / Visual alarm(s) had previously been silenced AND the trigger circuit is still in an alarm state - activating this switch will trigger the audible / visual alarms again (until silenced again).

    - A flashing lamp that will be placed inside the control cabinet that should flash to indicate an alarm state even if all other Audible / Visual alerts have been "Silenced" (Assuming due to the 50mA limitation of the DAQPro that this lamp, LED, etc should be placed somewhere in the alarm circuit between the trigger point & the reset switch).

    If some one could provide a basic circuit schematic then I should be able to take it from there. However any recommendations for specific hardware (relays, LED modules, etc) will also be graciously accepted.

    Thank you all in advance for your assistance. It is very much appreciated.


    Photo 1 (Overview)


    Photo 2 (Left Box)

    Photo 3 (Right Box)

    Photo 4 (Alarm Schematic)
  2. N2DFire

    Thread Starter New Member

    Apr 5, 2011
    Thanks to Edison and a little trial & error I think I have it.
  3. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    I am sorry. I must have missed the post.
    But it seems u have done it.
  4. N2DFire

    Thread Starter New Member

    Apr 5, 2011
    Hey R!f@@,

    Well the theory is sound and to be honest I just got lucky with figuring it out w/ trial & error.

    Now that I have the design, I need the parts. Theory is nice but I actually need to build something. :D

    Recommendations on parts is what I need now.

    I've tried Mouser & Digi-Key and I know enough about the basics (i.e. Voltage & Current) to be dangerous but I'm just not finding the components.

    Part of my problem is I don't speak the "language".

    I'd prefer to stay away from anything PCB / breadboard as I really am not comfortable with my skills at producing a reliable product for such a critical application. I'd rather stick with "screw down" components similar to what's in place already.

    What I need:
    The 2 Relays in the Alarm (30 VDC) circuit. (Planning to re-use the Dayton 1EGJ1 for the 5VDC Trigger / 30 VDC Alarm circuit interface)

    Also if someone has a suggestion for a 24VDC / 5VDC converter then I'll keep the Mean Well Power Supply as well & bring the Alarm Circuit down to 24 VDC

    Some sort of Flashing indicator for the panel to indicate an Alarm state - red preferred but as long as it's not white & flashes I won't be too picky.

    Other thoughts:
    I will ID the Telemecanique Switch and purchase a second one for the silence button.

    Fuse holders I should be able to find easily enough & I have plenty of SPST toggle switches for the A/V toggle.

    Again I'm not a pro at this by any means. Computer Programmer by Day - Firefighter/Paramedic/Instructor by night. Had a couple AC/DC fundamentals classes in college (a long time ago) - so any suggestions, cautions, or assistance is welcomed with open arms.

    Thanks Again.
    Last edited: Apr 9, 2011
  5. retched

    AAC Fanatic!

    Dec 5, 2009
    You may want to try Grainger or McMaster-Carr, as they will speak more the language of industrial sensors/automation.

    They both have great websites and catalogs.... and telephone support.

    You should be able to find all of your parts at either one of those two places.

    McMaster-Carr is a company you should get familiar with, as they stock tens of thousands of items in the sensor and automation categories.