I/P Valve PID Control

Hello,

Would anyone have a tutorial or a good example of programing a PID controller for a I/P valve positioner ?

Thanks

Are you talking about the internal PID in a 'smart' valve positioner that calculates the output response of the valve positioner, or are you talking about the PID control in a controller (using some process variable like pressure or flow) that generates a 4-20mA output that becomes the Process Variable/demand valve position signal that is transmitted to a valve positioner?

danw said:

Are you talking about the internal PID in a 'smart' valve positioner that calculates the output response of the valve positioner, or are you talking about the PID control in a controller (using some process variable like pressure or flow) that generates a 4-20mA output that becomes the Process Variable/demand valve position signal that is transmitted to a valve positioner?

Click to expand...

I am referring to the PID Control in a controller using pressure PV.

Please elaborate

wanher3 said:

I am referring to the PID Control in a controller using pressure PV.

Click to expand...

"Pressure" is not enough information.

Good news depending on what the Pressure sensor is, what the measured media is, (hydraulic, pneumatic, other), and how responsive the control valve is... pressure is generally easier than temperature loops with long thermal lag times.

Most of our pressure loops work well with simple PI loops.

Plastic

The valve's positioner should essentially be "transparent". The controller's PID output is telling the valve where it should be to achieve a pressure setpoint. More open or less open (more closed) or hold.

The PI tuning constants for the couple apps I was involved with had low gain (large proportional band) and a low amount of reset with no rate action at all.

But the values always depend on the system dynamics.

@wanher3

It would help people to help you if you described the situation better.

What are you actually controlling with the output of the PID (Pressure or Position for example)?

What is your desired outcome (force or Position)?

What is your feedback for the control loop? (pressure, force, position?)

consider drawing a sketch.

Nick