VDM Dosing project

Hi,

I would like to build a dosing system using the VDM ports for control. There is a great thread below where another member has done just that but i'm struggling to find the correct relay board with separate input supply and GND. the only ones i can find have the VCC - JD VCC jumper to allow a separate 5v feed (pictured). there is only one GRD though which would have to be shared with the RJ45 connection. I'm am not an electrical engineer but understand the basics and can solder well (used to make cables for a living). I also understand you do not wish to give out too much info on this subject incase people break their Apex's or set fire to themselves. I accept full responsibility for my own actions and the life if my apex.

If anyone can advise on a suitable 4 channel relay board, i would sure appreciate it!


Other thread: https://forum.neptunesystems.com/sho...M+dosing+pumps
Attachment 9554

Thanks,

Andy

Look for an optocoupler

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Quote:

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Originally Posted by zombie

Look for an optocoupler

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Thanks, i found the one with the Optocoupler but the power supply question still remains. The one in adamsonline's post has a separate live and GND to drive the relays. That model is no longer available and all the current ones have the VCC jumper that can be removed and a separate power supply connected on the JD-VCC side. that sees fine but it would mean that the VDM interfaces and the external 5V power supply are sharing the same GND. i'm not sure if thats ok?

see image (current model):

Attachment 9557

Sharing the same ground is fine. You just dont want the VDM actually driving the relays since the load can be too high.

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Most helpful, Thanks Zombie, now i just need to figure out the code!