avr_fred:
Sending 4-40ma from an Arduino will require a signal convertor. Google "pwm to 4-20ma converter" for both commercial units and circuit ideas.That will require a PID loop. There is an Arduino library for PID.
From your computer how? Serial? USB? Please be specific.
Thank you for the advice.
The pressure regulator accepts 4-20mA signal and output 0 to 10 bar in pressure on a linear scale. A programmable logic control should be able to do the job. But I wonder if I can achieve the same thing using Arduino. I want to use the serial monitor to input a pressure value. Let Arduino convert the value to 4-20mA signal and send it to the pressure regulator.
I know the Arduino will be connected to the PC using USB. I guess that I need to use serial pins to communicate with the pressure regulator. But I don't know how to do it yet.