harryting
Lifetime Supporting Member
Just to check my sanity even though I think I found the solution.
So, for this loop with long lag time we got 2 PID loops with the Outer Loop setting the setpoint for the inner loop in a 5380 processor. We used the standard PID ladder instruction and things looks good. The inner loop gets the outer loop setpoint.
We also have a feedforward component that feed into the .BIAS of the outer loop.. Again, it seems to work and we can see the CV change when the feedfoward changes.
However...
One problem that showed up is that on the activation of the loop. The output doesn't reflect the Feedfoward at all so with the slow tuning the output stays at 0 for long time. I think this is just how it works but I want to check with yall to make sure that I'm not missing anything. I can remedy this problem by jamming the FF into the output of the PID upon activation but wonder if there's more elegant or recommended way to do this.
So, for this loop with long lag time we got 2 PID loops with the Outer Loop setting the setpoint for the inner loop in a 5380 processor. We used the standard PID ladder instruction and things looks good. The inner loop gets the outer loop setpoint.
We also have a feedforward component that feed into the .BIAS of the outer loop.. Again, it seems to work and we can see the CV change when the feedfoward changes.
However...
One problem that showed up is that on the activation of the loop. The output doesn't reflect the Feedfoward at all so with the slow tuning the output stays at 0 for long time. I think this is just how it works but I want to check with yall to make sure that I'm not missing anything. I can remedy this problem by jamming the FF into the output of the PID upon activation but wonder if there's more elegant or recommended way to do this.
