[EMS Discuss] Magnetic Device Troubleshooting

EMAIL HIDDEN EMAIL HIDDEN
Sat Aug 31 07:57:05 PDT 2013


That was weird.  Premature emailation.  I swear, that's never happened to me before!

Anyway...  Have you put a meter on the gate of the offending MOSFET?  Some voltage must be being applied.  I would be
curious if it is the full voltage that is applied to the intended MOSFET.  Also, I would remove the Arduino completely
and replace with four switches and see if the problem persists.  (Remember that the MOSFETs won't turn off on their
own, the gate must be pulled to ground.)

-Darrell

> I have a device overview sketch that I am attaching to this post to help
> everyone get a bit of an idea of what the heck they are trying to help me
> with :D
>
>
> On Thu, Aug 22, 2013 at 6:45 PM, Cord Slatton <EMAIL HIDDEN> wrote:
>
>> Hello All!
>>
>> I have a device that I can only say so much about due to an NDA but I am
>> having a problem with and need a bit of advice. If I have not given enough
>> info or a diagram (though I cannot be too detailed on certain aspects) is
>> needed, please let me know.
>>
>> Thanks so much!
>>
>>
>> ------------------------------------------------------------------------------------------------------
>> I have Arduino based controller that turns on a single control board
>> input, which turns on one of 4 individual mosfet banks. When a mosfet bank
>> is on it allows current to flow which turns on an electromagnet.
>>
>> The magnets are hooked to the main power bus, all the same way, one side
>> going to positive and one to negative with a mosfet bank keeping it from
>> being always on.
>>
>> There is a bit of something in the magnet connector that is supposed to
>> cancel backflow EMF that could damage the controller, I am not positive
>> what is going on with that but it is super simple part wise, and I can get
>> the part number and post it if needed.
>>
>> This system used to work correctly in the past the way it is wired, but
>> not when I had it in my possession.
>>
>> Problem: When a magnet is activated another magnet is always active at the
>> same time.
>>
>> Known Information
>>
>>    1. The Arduino controller and the control board are working correctly.
>>    It sends a pulse to the correct mosfet bank. The correct indicator light
>>    activates and high voltage is sent to the corresponding mosfet bank.
>>    2. The mosfet banks seem to be working correctly, only the one
>>    receiving a signal activates.
>>    3. The magnet that is triggered by the controller does
>>    activate(correct behavior).
>>    4. The incorrectly triggering magnet is not triggered through
>>    induction and proximity does not matter.
>>    5. The same pairs of magnets always activate, even if rewired to the
>>    power supply in different configurations(magnets 1 & 4, 2 & 3)
>>    6. The only way to get a single magnet to activate is to remove it's
>>    paired magnet from the machine.
>>    7. The Arduino based controller I built is connected thusly: a ground
>>    wire to share the circuit's common ground and 4 control wires, each to
>>    individually turn on the pins on the device control board that drive the
>>    mosfets.
>>    8. Changing out the Arduino based controller for another control
>>    method(or manual control) does not change the behavior of the machine
>>
>>
>> --------------------------------------------------------------------------------------------------
>>
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