J
Hello gentlemen,
I'm having a bit of difficulty understanding how to correctly apply override control to a process I'm working with. I'm not so much concerned with the idea of "why to use it", but more how I'm supposed to effectively implement it.
Here's the layout: I have a reverse acting PID with a pressure PV; and a direct acting PID with a flow PV. The valve that I'm controlling is fail open.
Now I've seen a few threads about limiting the outputs of the non-controlling PID, but I'm having a hard time understanding what this is supposed to accomplish. Ultimately, regardless of what the "output" of my non-controlling PID is, the windup error is still going to occur, regardless of how I set my output limit.
I'd be tremendously grateful if someone could give me a hand with this. I don't want to be an engineer who just replicates things other people have done; I want to get a sense of the logic behind this type of process control.
I'm having a bit of difficulty understanding how to correctly apply override control to a process I'm working with. I'm not so much concerned with the idea of "why to use it", but more how I'm supposed to effectively implement it.
Here's the layout: I have a reverse acting PID with a pressure PV; and a direct acting PID with a flow PV. The valve that I'm controlling is fail open.
Now I've seen a few threads about limiting the outputs of the non-controlling PID, but I'm having a hard time understanding what this is supposed to accomplish. Ultimately, regardless of what the "output" of my non-controlling PID is, the windup error is still going to occur, regardless of how I set my output limit.
I'd be tremendously grateful if someone could give me a hand with this. I don't want to be an engineer who just replicates things other people have done; I want to get a sense of the logic behind this type of process control.
