Go Down

Topic: Driving proportional solenoid valve using PWM (Read 286 times) previous topic - next topic

zeus2kx

Oct 11, 2018, 03:23 pm Last Edit: Oct 11, 2018, 03:27 pm by zeus2kx
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


jremington

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.

zeus2kx

#2
Oct 11, 2018, 09:01 pm Last Edit: Oct 11, 2018, 09:10 pm by zeus2kx
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.

jremington


zeus2kx

They don't support this particular model anymore.
However, they proposed the attached controller.

Robin2

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

zeus2kx

I have nothing to contribute - this stuff is beyond my pay grade.


Well, thanks anyway.

jremington

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.

zeus2kx

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.

jremington

Quote
I can rebuild this circuit
What circuit?

zeus2kx


jremington

#11
Oct 13, 2018, 12:23 am Last Edit: Oct 13, 2018, 12:24 am by jremington
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.

zeus2kx

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.


zeus2kx

I will very appreciate if someone helps me get to a solution.

Thanks.

jremington

#14
Oct 18, 2018, 05:16 am Last Edit: Oct 18, 2018, 05:29 am by 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.


Go Up