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Topic: Driving proportional solenoid valve using PWM (Read 3080 times) previous topic - next topic

zeus2kx

#30
Nov 18, 2018, 07:43 pm Last Edit: Nov 18, 2018, 07:44 pm by zeus2kx
Hi guys,
I built the circuit (below) for PVQ31.

I tested with an input in the range 0-5VDC (not PWM) but the valve opened only at 4.6V.
Therefore the entire opening of the valve was in the range 4.6 - 5V.

Just for testing, I used 0-10VDC and again the valve opened at 4.6V. Here I had a wider range of operation, i.e. in the range 4.6V - 10V.

I would prefer modifying the circuit (needs your suggestion) to drive in the 0-5V range.

Kindly suggest.

Thanks.

jremington

#31
Nov 18, 2018, 08:11 pm Last Edit: Nov 18, 2018, 08:47 pm by jremington
The circuit is performing as expected.

4.6V across the input divider gives about 0.16V input to the op amp.  That corresponds to a current of 0.16A across the 1 Ohm resistor, which is evidently what it takes to open the valve.

If you increase the 1 Ohm sense resistor to 10 Ohms and reduce R1 to about 560 Ohms, 5V input should then lead to about 190 mA maximum coil current. Reduce R1 further to increase the valve current at any given input voltage.

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