Any electronics people? 12v output and 10v input

[kingandy2nd]

I have an aquarium computer that I can programme to send out 0-10v outputs via RJ45 cable.

I want to use the function to activate (and keep on) a 12v solenoid valve.

As a first attempt I bought a step-up voltage converter. However on power up it triggers the solenoid momentarily but then goes off (and the display on the step-up) goes off.

I can only assume there isn’t sufficient wattage/amperage (don’t know the right term) to sustain the circuit.

Therefore I was thinking of something like this:

http://vi.raptor.ebaydesc.com/ws/eB...=171920&pm=1&ds=0&t=1553761570235&cspheader=1

My thinking being that with an external power supply and a 12v output this would work...however the information isn’t too clear.

Can anyone advise if this will work as I want? Ie switch on and off based on the voltage input from the 0-10v the aquarium computer? Thanks

 

[bernardgreen]

0-10v outputs

0-10v signals are almost always a control signal that controls something that is supplying and/or controlling a variable. Speed, brightness, amount of heat, temperature, etc

Solenoid valves are not usually variable. They are either fully open or fully closed.

I suspect that when the control voltage is close to 0v the solenoid needs to be closed and when the control voltage is close to 10v the solenoid needs to be open.

That said a flow control "solenoid" ( more than just a solenoid ) could be a variable opening controlled by the 0-10 volt control signal.

The first option is easy to achieve with a 12 volt power supply and a relay with a high impedance 10 volt coil.

To achieve the second option would require a lot more information about the solenoid ( flow controller ) and the aquarium computor.

The arcade power supply that you linked to is totally unsuitable for yours and most other applications.

 

[kingandy2nd]

Hi there,

Thanks for the input.

Yes the 0-10v is a control signal, but I can programme that to run at 0 to 100% so I can effectyuse it as an on / off signal.

It is the first option I’m attempting to achieve with a simple on/off of the diaphragm solenoid.

I will look for the part you mentioned and will come back for confirmation of the correct item.

Thanks for your feedback

 

[Nozzle]

You need a relay, thyristor or Triac. How much current can the 0-10V output sink/source? If this is enough to actuate a solenoid coil, you're in business. If it's not, you need an extra stage with a transistor (look up BC108) and then drive the relay coil with that. Using a relay solves some problems, also gains a few. You need to use a diode "reverse biased" to prevent the backemf of the de-energising coil from destroying the transisor. The de-energising coil of the solenoid has a similar effect, but the contacts in the relay shold handle it. Is the solenoid AC and DC rated? It may only need momentary operation to get it to open. If permanently energised against a spring it'll get warm

Nozzle

 

[bernardgreen]

It is the first option I’m attempting to achieve with a simple on/off of the diaphragm solenoid.

In which case the details of the diaphagm solenoid are needed, operating voltage and resistance ( or operating current ) to select a suitable power supply.

How you fix / house the relay and power supply will determine the type of relay.

 

[kingandy2nd]

Thanks for the continued contributions guys, I really do appreciate it.

The solenoid is this particular one here:

https://www.amazon.co.uk/DIGITEN-So...encoding=UTF8&psc=1&ref=ppx_pop_dt_b_pd_title

The 0-10v output from the aquarium controller is all the info I have about it at the moment but I will attempt to find out some more information for you.

 

[Nozzle]

You need a relay capable of carrying at least 0.5 amp, with a breaking current much higher.

Something like this: https://cpc.farnell.com/omron-elect...2-5vdc/relay-signal-pcb-dpdt-5v-dc/dp/SW04917

With the 178ohm coil resistance, continual current draw will be ~30mA @ 5V, so long as you limit your 0-10V controller so it never goes above 5V then the coil will stay healthy. Other thing you can do is apply +5V initially to get the coil to draw relay closed, then reduce the voltage back a bit once the coil is energised. This will limit the current draw from your device. Which you're yet to tell us what it is capable of sourcing.

Imperative to use protection diodes with any electrmagnetic devices where there field quickly break down, like this application. Once you have you controller satisfactorily switching the relay, then go on to use the relay as a switch for the solenoid.

Use correctly rated fuses too..

Nozzle

 

[nickjb]

I'd use a FET. You can get little boards on eBay. They'll take a range of inputs, easy to wire up and will happily drive the solenoid. You'll need a separate power supply to make the 12v.

This sort of thing, this a 5v input. https://www.ebay.co.uk/itm/IRF520-M...518999508?hash=item3623365dd4&redirect=mobile

 

[bernardgreen]

With the 178ohm coil resistance, continual current draw will be ~30mA @ 5V, so long as you limit your 0-10V controller so it never goes above 5V then the coil will stay healthy.

but loading a 0-10v control port with 178 ohm coil may not be "healthy" for the controller. Until we know the current capacity of that 0-10 v output there can be no definite solution without using an amplifier capable of driving the relay coil.

 

[kingandy2nd]

Hi all,

Thanks for the continued help.

I have been provided with the attached document (unfortunately in German) and a link to a thread on another forum which provides some information:

https://forum.aquariumcomputer.com/showthread.php?2605-10V-port-schematic

Unfortunately it doesn't give a great level of detail, but google translate tells me this:

Remarks: • With pins 1 and 4 or pins 1 and 6, the coil of a relay (rated voltage 12V) are driven. This relay picks up when dimming position is greater than 0%. Attention: Only load outputs with 20mA, do not forget freewheeling diodes!

I like the idea of the FET if that will correctly work - as the less I need to 'build' the better

Regards
Andy

 

[kingandy2nd]

Hi guys,

I’ve got the specs from the aquarium computer now. I am planning on using the L-Ports (in the top table), or if you think it’s a better idea I can use the S-Ports but those are not variable voltage.

Any more suggestions?
Thanks
Andy

 

[Nozzle]

Use that L-port pin 4 or 6 to drive the FET Gate or relay coil. Use the FET source or drain or contacts of the relay to drive the solenoid. Forget about the analogue side

Nozzle

 

[endecotp]

Pins 4 and 6 seem specifically intended for directly driving a relay, so use those!
Don’t forget the flyback diode.

 

[kingandy2nd]

Thanks guys - FETs arrived today...but no wiring diagram so will need to work that out next

 

[endecotp]

You don’t need FETs, those open-collector outputs can directly drive a relay.