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PID relay output to control solenoid valve question

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birzzz

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Hi,

I have a PID controller which has it's output configured as a relay. It is fed by 220vac. If I want to use it to control a solenoid valve (24vdc) can I just purchase a AC to DC converter and hook up the relay output from the PID controller to the AC input on the converter and the DC output to the solenoid valve?

Thanks,
 
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Your plan seems perfectly reasonable, as long as the "converter" (aka AC adaptor) is happy with 240VAC input, puts out 24VDC, and can provide enough current for the solenoid's needs. My quick check did not reveal what those needs are...
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Konadog

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You say that the 220v feeds a relay, are you sure the output of the relay is 220v, or is it another voltage out, or even a dry contact out?
 

gavinr

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A relay output is a dry-contact output. On PIDs they are typically single pole NO (normally open) contacts. Think of it as a switch that is triggered by the PID. You need to wire this switch in series with the load, i.e. your solenoid. Wire one OUTPUT terminal of a 24V DC transformer directly to the valve, and the other one to a PID relay contact. The third wire goes from the open PID relay contact to the open valve contact. AC is NOT switched at the relay. It goes directly to the transformer input.
 
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birzzz

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OK thank you guys,

So if I understand well, my first assumption was good, albeit my converter can provide enough current.
 
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