Does this circuit work?

Discussion in 'General Electronics Chat' started by MrW01f, Feb 27, 2017.

  1. MrW01f

    Thread Starter New Member

    Feb 27, 2017
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    Hi,

    I have a load item that need 12v and 1.2amp so I use a power adapter of 12v and 2amp.
    I use a time delay relay that can handle up to 5amp and the trigger use 5v
    The switch a use to trigger my time delay relay work on 12v but doesn't support more than 0.5amp
    I use a relay to use my switch on the 12v and trigger the 5v on the time delay relay.
    I would like to know if this schema can work safely for my switch?
    Diagram-Float.png

    Regards,
    Frank
     
  2. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Umm, your diagram doesn't show what the connections are on your two "boxes".

    Do you have a schematic that shows what's in the boxes? Which are the coil connections, more importantly what the contact arrangement is? Do you have manufacturers and part numbers of the relay and timer? Maybe it's too much to hope for, maybe a datasheet for those components?
     
  3. MrW01f

    Thread Starter New Member

    Feb 27, 2017
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    The "load" is a Tunze Dosing pump (12vdc - 1.2A)
    The Time Delay Relay is the one from http://bit.ly/timer17 (12vdc - 5A)
    The Switch is a Float Switch from Digital Aquatics (12vdc 0.5A)
    The Relay is just a generic Car relay (12-14vdc - 30/40A)
     
  4. MrW01f

    Thread Starter New Member

    Feb 27, 2017
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    is it already working, I just want to be sure I won't fry my float switch as it can only handle 0.5amp.

    Thanks
     
  5. djsfantasi

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    It doesn't look like you timer module is ever going to see a 5V signal. The timer module is wired to the common contact of the relay. The NC contact is floating. The NO contact is connected to ground. Where is the 5V coming from?

    This is why I asked for a datasheet. If you had referenced one, you would have seen this, too.

    There may be more. I stopped at that.
     
  6. MrW01f

    Thread Starter New Member

    Feb 27, 2017
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    5v is provided by the Time Delay Relay
    at first, I connected the Float switch on the trigger of the Time Delay Relay and it didn't work, after I tested the voltage on it with my multimeter, I realize the output was only 5v and not 12v.
    that's why I use the Car relay to trigger the time delay on the 5v from a 12v switch
     
  7. djsfantasi

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    I still don't see how the timer works. When you activate the switch, the node labeled 5V on the timer module will be connected to ground. If the timer module is supplying 5V on that node, you'll have a short.
     
  8. MrW01f

    Thread Starter New Member

    Feb 27, 2017
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    the 5v need to be shorted.
    I could replace the relay by a press button on the trigger (labeled 5v) to ground and it will work
    I just labeled it 5v because it's the voltage I get from it and it's not enought for my float switch to work
     
  9. mcgyvr

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    Oct 15, 2009
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    Can we assume this is for ATO? (auto top off)
    If so why are you using a timer?

    But even so.. There is no point in using the relay..
     
  10. MrW01f

    Thread Starter New Member

    Feb 27, 2017
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    no, it's for semi-auto water change
    the time delay is for the pump to work 3 more seconds after the float switch trigger
    and the pump from my clean water start 3sec after the pump from my sump started
     
  11. mcgyvr

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    So if the trigger input on the timer just needs to be pulled to ground replace the relay with the switch just going to ground..
    The trigger input is low current so the float is more than capable of pulling it to ground.
     
  12. MrW01f

    Thread Starter New Member

    Feb 27, 2017
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    if I connect the float switch to the trigger directly, there is not enough power to make the float switch work.
     
  13. MrW01f

    Thread Starter New Member

    Feb 27, 2017
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    I found that the coil of my relay is 1amp, so I'll need to find Something else that use less current to replace it
     
  14. mcgyvr

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    huh? A float switch doesn't need power? Its just a switch isn't it (no part number supplied)?

    See page 12 of the timer manual for proper hookup of the float switch..
     
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  15. MrW01f

    Thread Starter New Member

    Feb 27, 2017
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    I just tried to connect the float switch between +12v and the trigger cable and I only have 7v, not enough to make the float switch work.
    of all the test I did, logic or not, the float switch only work when I apply 12v on it

    I don't have any model number, Digital Aquatics only make 1 model as I know.

    I already contact both company, for the float switch and for the time delay relay, but can't get anything from them.

    do you know any low current 12v relay that I could use instead of my coil relay that pull to many amp?
     
  16. djsfantasi

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    I give up! None of what you are saying makes any sense to me.,. Sorry.
     
  17. BR-549

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    From what I can gather....the float switch should be able to control the timer relay. No trigger relay needed.

    So that's two.
     
  18. mcgyvr

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    Per the document I saw float should go to ground not 12V
    The timer has a pull up resistor to 5V already

    Trigger Pin----Float Switch----Ground
     
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