Hi guys,
I have an old proportional solenoid valve which can be proportionally opened and closed in the supply voltage range of 0-6VDC.
This valve does also support current driving but I want voltage control using PWM (0-5V).
Now how can I use Arduino PWM when I am limited by current?
Can I use easydriver? If so, how do I wire and code?
Thanks.
Z
You will need a voltage controlled, constant current driver. A motor driver will not work.
Google "arduino proportional valve control" for several forum entries and DIY projects.
Hi,
In general Solenoid Proportional Valves (SPVs) are constant voltage (CV) and variable current driven.
In this case I could think of CV and vary the current by a circuit similar to below..
But this is tricky. More than an year ago I tried a different SPV but didn't have much success.
Therefore for this particular valve (tested by bench-top power supply by varying input voltage) I wanted to vary voltage somehow by using arduino PWM.
Without powering this valve, the coil resistance is 5 ohms.
Would you recommend a circuit?
Thanks.
What does the manufacturer recommend?
They don't support this particular model anymore.
However, they proposed the attached controller.
iQ Signal Amplifier - Tech Data.pdf (34.3 KB)
@zeus2kx, for some strange reason you sent me a PM asking me to look at this Thread.
I have nothing to contribute - this stuff is beyond my pay grade.
...R
Robin2:
I have nothing to contribute - this stuff is beyond my pay grade.
Well, thanks anyway.
The circuit posted in reply #2 is not a good idea, because the RFD3055 is not a logic level MOSFET.
If you had taken the trouble to do the Google search suggested in reply #1, you would have found this discussion, with suggested circuits, near the top of the list.
I used FQP30N06L instead.
Its a logic level N-Channel MOSFET with Vgs lower than 3V.
I saw that post you mentioned and luckily I had built this circuit as well in the past. It could only open the valve but not proportionally in the PWM range.
I can rebuild this circuit but kindly suggest changes based on this valve.
Thanks.
I can rebuild this circuit
What circuit?
In order to design a proper control circuit, you either need the valve datasheet, or experiment to determine how much current is required to obtain a certain flow.
The 6V rating combined with the 5 Ohm coil resistance suggests that 1.2 A is required to open the valve fully.
jremington:
The 6V rating combined with the 5 Ohm coil resistance suggests that 1.2 A is required to open the valve fully.
Exactly.. actually 1A since I want 5V PWM. Valve won't be completely open but that's alright.
So the operating current range is 0-1A.
I will very appreciate if someone helps me get to a solution.
Thanks.
I would modify this circuit to deliver about 1.2A max. To do that, the voltage divider has to deliver 1.2V to the op amp pin 3, when 5V is input. R1=3.3K, R2=1K should produce about 1.16V.
The valve drive and op amp power supply voltage must be greater than about 8V. 10-12V should be OK but you will need a heat sink on the power transistor.
jremington:
I would modify this circuit to deliver about 1.2A max. To do that, the voltage divider has to deliver 1.2V to the op amp pin 3, when 5V is input. R1=3.3K, R2=1K should produce about 1.16V.The valve drive and op amp power supply voltage must be greater than about 8V. 10-12V should be OK but you will need a heat sink on the power transistor.
Sorry for the long delay. I was away for a while and also took me some time to arrange all the required parts.
Good news is that it is working! Thanks a lot.
I used a pot for PWM. A small issue is that there is a high pitch sound, though not loud, coming out of valve. Is there a way to suppress this sound?
I have a different valve (PVQ31 0-165mA 24V).
Resistance of the coil (without exciting) is about 100 ohms.
What changes do you recommend in the circuit?
Thanks.
TomGeorge:
Hi,
You will need a PWM frequency of 1.2kHz.
I used digital pin 5 which has PWM frequency of about 980Hz.
Hi,
Good to see you have a result.
What are you using as a power supply for the solenoid?
Can you post a copy of your circuit diagram please?
Thanks.. Tom... 
Datasheet don't say anything about suitability for PWM or whether dither is needed. Good luck. 
Is there a way to suppress this sound?
No, but you could try different PWM frequencies.
For the new coil, you have to change the circuit constants to result in 165 mA max = 16.5V across a 100 Ohm coil. Study the design hints in reply #14.
That cannot be done without a higher voltage power supply, say 24V.
