HI Guys,
I have a valve from SMC PVQ31 24V model with 165mA. Resistance of the coil is 110 ohms. I am using this circuit: (FET is FQP30N06L)

I actually like to drive this valve using Arduino PWM - which in the range 0 -5V.
Problem is, this circuit only drives the valve when input PWM voltage is above 2.2V.
At 5V input, current I measured was 80mA.

Kindly suggest a solution.

Thanks in advance.

Z

 

The PWM voltage from the Arduino is a 0V to 5V digital pulse stream with variable duty-cycle, not a 0-5V signal.
The average value of the PWM signal can go from 0V to 5V.

With 5Vdc on the M1's gate, the current through the value should be over 200mA.
What is the drain voltage when the gate signal is 5V?

 

Hey thanks,

The PWM voltage from the Arduino is a 0V to 5V digital pulse stream with variable duty-cycle, not a 0-5V signal.
The average value of the PWM signal can go from 0V to 5V.

I agree.

With 5Vdc on the M1's gate, the current through the value should be over 200mA.
What is the drain voltage when the gate signal is 5V?

I measured at gate to ground which was 5V and drain to source was 0V.

 

I measured at gate to ground which was 5V and drain to source was 0V.

So then what was the current?
You originally complained that it was only 80mA.

 

Have you looked at Chart 1 on page 876 of the the datasheet? The valve doesn't start to allow flow through it until current through the valve is around 80mA (when using 24V.)

I'm not entirely sure what you were referring to with your current measurements, but it looks like 80mA through the valve is roughly the zero point in terms of valve motion. Any current through the valve that's less than 80mA is likely to be wasted energy that doesn't get any work done.

This is pretty similar to my experiences with some Burkert proportional solenoid valves I've been experimenting with. They don't allow any flow through them until roughly 40-50% duty cycle

 

Here's the referenced chart, to save people some mouse clicks:
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