4-20ma valve control with PIC

[otuzsubat]

pic 4-20ma

I want to control a valve with PIC microcontroller. The valve can be controlled by 4-20mA signal. I think the shema below is suitable. Before complete design, i need your ideas. Is there any easier way to succeed this? What could you suggest me?

 

[IanP]

4-20ma with a pic microcontroller

Another option is to use dedicated 4-20mA current generators:
**broken link removed**
Instead of using ADC+V/I converters you can use digital potentiometer + one of these circuits .. but that is just another option ..