4-20 mA controlled 0-24vdc potentiometer??

[ndzied1]

These look interesting

We use the decides from PWM controls in this application very successfully. Although we represent other companies which make similar devices and have no affiliation with PWM controls, we prefer them for one-off applicatios. Especially useful is the manual mode.

 

[rigicon]

Is this controlling the swash plate on the pump to vary the flow and or pressure. I agree with Alaric & others a proportional control card which controls not only the voltage but the constant current required at a particular setting.
eg Vickers / Rexroth. These cards can even provide spool position if the valve has a LVDT fitted closing the loop if actual flow/pressure is measured. Controlled via 0-20mA, 4-20mA +-10V etc the normal PLC analog output.