omron relay activation circuit help

Discussion in 'The Projects Forum' started by minkey01, Sep 26, 2015.

  1. minkey01

    Thread Starter Member

    Jul 23, 2014
    171
    0
    Could someone help me understand how this one relay (K401) works in this circuit? I don't understand how points 7,10, & 12 control this relay.

    This looks to be a 4PDT DC24V Omron relay. Labelled K401 in the jpeg and highlighted yellow. The actual part has this writing on it : Omron Type MY4 -02-US-L DC24

    The relay controls those 4 switches above it in yellow. They are shown in the off position. What they are switching was left out for clarity and it doesn't really matter. Except for the first switch, not sure what it is doing.

    I wonder if I even need connection 7.

    Ideally I just want one button to activate this relay from the power supply shown in the jpeg.

    Any ideas on how to modify this circuit?

    Thanks!
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
  3. minkey01

    Thread Starter Member

    Jul 23, 2014
    171
    0
    Thanks, Mike! That is exactly what I need. I just never heard of its name, so couldn't search for it.

    Check out this new circuit I came up with, attached.

    Does this new circuit look right to you? Polarity ok? Buttons ok? Does that diode,resistor, and cap look right?

    Thanks again!!

    omron relay_rev2.jpg
     
  4. KeepItSimpleStupid

    Well-Known Member

    Mar 4, 2014
    1,144
    203
    No, the SET button has to be directly across the normaly open relay contacts. The NC reset button is in series with that combination.

    Now wire the above combination to power, the relay coil and ground.

    When you trace the circuit, the relay NO relay contacts when closed will turn on the coil .OR. the push button will turn on the coil.

    The LED and resistor combination go across the coil. 47 ohms is a bit low. Try R <= (24-2.1)/15e-3
     
  5. minkey01

    Thread Starter Member

    Jul 23, 2014
    171
    0
    Like this?

    omron relay_rev3.jpg

    What resistor value would you recommend? I think this relay resistance is about 636 ohm from looking at some online specs, if that helps with the calculation. It also says 24v for the relay.
     
  6. minkey01

    Thread Starter Member

    Jul 23, 2014
    171
    0
    i was using that size resistor, because that is what they had in the original circuit.
     
  7. minkey01

    Thread Starter Member

    Jul 23, 2014
    171
    0
    also, it's not an LED. just a diode
     
  8. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Yes that will work
    The way he drew it will work just fine.
    No that way won't work at all.
     
  9. KeepItSimpleStupid

    Well-Known Member

    Mar 4, 2014
    1,144
    203
    Strantor:

    Look at his revised circuit again.

    The diode, cap and resistor seem to be adding some sort of delay.

    I looked at the original drawing and I'm not sure what he wants though or if it's compatible with the original drawing?
    I didn't see it initially.

    The second drawing is indeed a latching relay, but it has some built-in delays for whatever reason.

    Normally, one would eliminate the cap, low value resistor, series diode and put a diode backwards (so it normally doesn't conduct) across the coil.
     
  10. minkey01

    Thread Starter Member

    Jul 23, 2014
    171
    0
    to clarify :

    the only thing that is needed from the original is the power supply and the relay.

    it doesn't need to function like the original setup. the new function of the relay is just to turn it off and on with the two new latching button setup. nothing else.

    personally from looking at both of my circuit revision paths, they both will work. but people seem to be saying one wont work or the other wont work. not sure who to believe here.

    i don't need any timing. i was just grabbing the cap, diode, and resistor setup because i thought it was maybe a safety thing. how should i setup the cap, diode, resistor? someone can help with a sketch?

    thanks!
     
  11. minkey01

    Thread Starter Member

    Jul 23, 2014
    171
    0
    After comments about the last post check this out...


    How about the power supply for this relay? ;)

    Look at this new jpg. Is this the right circuit to extract from the original schematic for the power supply for the relay (please see original post and jpg schematic before commenting)?

    It is a transformer on the left that plugs into the wall USA. The output is 11.5V x 2 centered tap thing AC. Now we need the right circuit to bring it to DC for the relay. Are these the right components? From the original schematic it looks like they were changing to different amounts of DC in a few different branches. Trying to make sure I have the right circuit.

    omron relay_rev5.jpg
     
  12. minkey01

    Thread Starter Member

    Jul 23, 2014
    171
    0
    or you have the old set button location :

    omron relay_rev6.jpg
     
  13. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Your rev2 will not work because as soon as you press SET, the coil begins to energize and the contact begins to shift from the NC contact to the NO contact, but as soon as it breaks from the NC contact, it goes into a deadzone between contacts where the coil is no longer energized. For 90% of the travel distance of the contact, there would be no motive force. The only thing that would theoretically be moving the contact for that 90% travel would be inertia from the first 10%, and that's not enough. If you don't believe me (I don't blame you), go try it out. Actually, go try it out either way. Nothing to lose, only knowledge to gain. I've tried it before, and it didn't work for me; maybe it will for you, and you can come back and teach me something.
     
  14. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    With regards to timing and the cap/resistor combo, i don't know. it does appear to be some sort of delay, but is that it's only function? 47ohms seems awefully high value to be in series with a 12v relay coil whose own resistance might even be lower like 30ohms. What's the voltage rating printed on the relay? If it's 12V applied and 12V rated then it should be safe to remove the resistor and cap, but verify first. It could be a 6v relay or something.
     
  15. minkey01

    Thread Starter Member

    Jul 23, 2014
    171
    0
    4PDT DC24V Omron relay. The actual part has this writing on it : Omron Type MY4 -02-US-L DC24

    So it looks like a 24V relay and I think it has 636 ohm resistance.
     
  16. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Ok then it should be safe to get rid of the resistor and cap and feed it 24v straight from the rectifier.
     
  17. KeepItSimpleStupid

    Well-Known Member

    Mar 4, 2014
    1,144
    203
    See PDF page 6. http://escventura.com/manuals/ab_typicalWiringDiagrams_rg.pdf

    Some of these schematics are written in relay ladder logic form.

    In 'industry" your usually controlling a big contactor and that contactor has an "Aux contact" which is a low current control contact used for the controls.

    ==

    I used one in a wierd application: I put an auto-answer modem on the end. If I was running an experiment and there was a possibility of a power failure due to rain, I'd set things up this way.
    If the modem answered it was likely OK, if it didn't then likely not. I only implemented start and a lighted push button.

    ==

    In other uses (A motor starter), I had OFF/ON/AUTO and START/STOP so that a stop on power fail would be optional. Some three-phase protections was purchased complete.
     
    Last edited: Sep 27, 2015
  18. minkey01

    Thread Starter Member

    Jul 23, 2014
    171
    0
    last question :

    With these push buttons which are effectively dc switches, do I need to be concerned about sparking or arcing or anything like that? Do they need caps across them to suppress this or anything?

    Thanks homies!
     
  19. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    the way you were drawing the diode across the coil starting in post #11 is called a flyback diode configuration. that should remedy the spikes if you install it.
     
Loading...