I am wanting to control the flow rate of a pressure regulator (https://www.festo.com/net/SupportPortal/Files/505126/VEAB_2018-05a_8080669g1.pdf). My idea is to control this with a PWM signal 0-5v.

The signal requirements for the PPR is either a voltage of 0-10v or current controlled 4-20ma.

Option 1: Now if you had a MCU with PWM could you use put a 125 ohm resistor to the input of the regulator if it was current controlled? As at 0.5v you have 4ma and at 5v you have 20ma.

Option 2: I could use a mosfet but I am unsure on what I a looking for if I want use one. I know the VGS(th) must be less than 5v to be used for a MCU but how do I know how much voltage will flow when the voltage at the gate is 1v or 5v?

I am open to what you guys think could be best and any help would be appreciated.



I suppose that could work, it wouldn't be very accurate current control however. There are better ways.

A better circuit would be one like this which is for controlling current from 4mA to 20mA :

enter image description here Source: 4-20mA Output from Arduino

There are also other circuit in the question:

I've used variations of this one before many times:

enter image description here

  • \$\begingroup\$ Can you explain the circuit operation in circuit 2? \$\endgroup\$ – Newbie May 12 at 1:55

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