program dropping out when relay output is turned off
James D. Lane
Posts: 12
Hi all,
I have a 2p40 set up to drive some 5Vdc potter brumfield relays.· The program runs great, it turns on 2 or 3 relays that inturn turn on some solenoid valves.· There is an opamp buffer IC with the clamping diodes built into it tied to the 2p40 outputs that drive the relays.· When one of the outputs is turned off the entire program stops/resets as though the 2p40 was reset from some sort of voltage spike or drop.· I am sharing the same ground among the opamp, 2p40, and the relays, do I need to isolate the ground or has someone seen this phenomenon?· and do you have a solution?
thanks,
James D. Lane
·
I have a 2p40 set up to drive some 5Vdc potter brumfield relays.· The program runs great, it turns on 2 or 3 relays that inturn turn on some solenoid valves.· There is an opamp buffer IC with the clamping diodes built into it tied to the 2p40 outputs that drive the relays.· When one of the outputs is turned off the entire program stops/resets as though the 2p40 was reset from some sort of voltage spike or drop.· I am sharing the same ground among the opamp, 2p40, and the relays, do I need to isolate the ground or has someone seen this phenomenon?· and do you have a solution?
thanks,
James D. Lane
·
Comments
·· This is most likely attributed to noise produced by the solenoids de-energizing.· Do you have diodes on them?· Also you may need to filter your supply a little bit to clean up such noise spikes as can be produced on the power supply lines.
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Chris Savage
Parallax Tech Support
csavage@parallax.com
The opamp ic's I am using have diodes built into them. Those are the only diodes in the circuit. I have capacitors on both the output and the input of the 5VDC power supply.
James
·· Usually this is what's happening.· Of course, without seeing what you have it's really a guess, but a most likely guess, nonetheless.· Do you have details of the voltages, and the part numbers and how they're connected?
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Chris Savage
Parallax Tech Support
csavage@parallax.com