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Topic: 4 relay shield (Read 265 times) previous topic - next topic

Wosche

hey community,

as the subject says, i have some questions about the 4Relay shield.

I have to switch on/off a magnetic valve for compressed air (approximatly 3bar). The valve has the option of 12V DC or 24V Dc with a 1W coil.

is the Relay shiled useable for this? (I think yes, but it's better to ask)

And what kind of power supply would you suggest?

kind regards,
Wosche

Robin2

#1
Sep 17, 2018, 12:22 pm Last Edit: Sep 17, 2018, 12:24 pm by Robin2
You need to post a link to the datasheet for the Relay Shield.

Relays usually have their voltage and current limits printed on them.

...R

Two or three hours spent thinking and reading documentation solves most programming problems.

Wosche

Of course. It is the general 4 relay shield of the arduino store for example 4 relay shield.
I know i only need one relay, but i haven't found something that suits more.

Also i would need a power supply. what kind of would you suggest? especially for this low power valve?

Robin2

Unfortunately that link does not list the current and voltage rating of the relays. I suspect it would be quite satisfactory but I can't be certain.

Relay boards like this one are widely avaliable with different numbers of relays. They are cheaper, but not as convenient as a shield.

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

Wosche

Allright I have seen these too. And they should suit this project.

What kind of power supply would you suggest? I wanted to take a simple plug in power supply and rip up the two wires but I couldnt find anything with a current that low.

Robin2

It does not matter if a power supply can provide too much current - the device will just take what it requires. The important thing is to choose the correct voltage.

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

Wosche

#6
Sep 17, 2018, 03:35 pm Last Edit: Sep 17, 2018, 03:38 pm by Wosche
Summa sumarum ... Just to clearify. 12VDC/0->1Aplug in power supply to the relay and gnd to the coil of the valve. Controlled with a 5V digital output of the Arduino.

Schematic attached.

Should i use a diode attached to the coil?

Kind regards and thanks for the help
Wosche

Robin2

Image from Reply #6 so we don't have to download it. See this  Simple Image Guide



...R
Two or three hours spent thinking and reading documentation solves most programming problems.

Robin2

That looks OK. A diode across the relay contacts (to dissipate the energy in the coil when the relay opens) would be a good idea. Arrange the diode so it does not normally conduct the battery power.

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

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