Using 3 channel controller to run relays.

[Pauls]

Can I use the 3 channel controller to switch 3 relays? I know there will be a slight delay and they won't be on and off rapidly. It will be used to turn something on for a few mins then off again for 5 to 10 mins.

[Craig]

Yes you can wire a relay to the outputs of the DC Controllers. You may need to add a diode to prevent fly-back to protect the controller. You may also need a resistor depending on the relay.

Craig

[Pauls]

(15-08-2020, 07:45 PM)Craig Wrote: Yes you can wire a relay to the outputs of the DC Controllers. You may need to add a diode to prevent fly-back to protect the controller. You may also need a resistor depending on the relay.

Craig

Thanks for the reply. It's a solid state relay same as the one below in the link. Only going to be using 2 of the channels. It looks to have resisters and possibly diodes on the board so hopefully it will be ok. 

https://www.ebay.co.uk/itm/303640179576 

Will give it a try and see what happens. Lol.

[Craig]

Should work but looks like the relay output will be inverted. If I have read it right 0v is on, so the relay will be on when the channel output is off.

Mechanical relays often have normally open and normally closed connections so you can choose which way round you need.

Craig

[Pauls]

(15-08-2020, 09:44 PM)Craig Wrote: Should work but looks like the relay output will be inverted. If I have read it right 0v is on, so the relay will be on when the channel output is off.

Mechanical relays often have normally open and normally closed connections so you can choose which way round you need.

Craig

Thanks. I just used that as an example one. The one I have is normally open. Will give it a try when the additional controller comes I have ordered.

[Pauls]

Hi Craig

controller arrived today but I have hit a snag, the relay board needs a positive supply to activate the relay, but on the controller the positive is always high as its the negative that is switched, any ideas or do I need to go back to the drawing board.

[Craig]

Yes all the DC controllers switch the negative side. You could possibly convert the controller output to a positive switch with additional electronics (such as a transistor).

Other than that use a mechanical relay as they work if either positive or negative is switched. Should be easy to find a 240v 2amp rated one.

Another option, if your solid state relay only needs 5v and a few milliamps (to activate the relay), you could remove the mofsets from the 3 channel controller and use the output signal directly from the microcontroller. They will be a 5v+ signal, upto 20ma I think.