Lakee911
Member
Hello,
I'm having a lot of trouble tuning a PID loop on a SLC 5/05. Can someone tell me if I'm doing something wrong? Please see attachment to this thread.
Basically, I have a gate opens into a wetwell. I am opening the gate to allow flow into the wetwell. The wetwell has a PID loop (that works just fine) that varies the speed of pumps which maintain a wetwell level. What comes in, gets pumped out. After the pumps, there is a magnetic flow meter. The loop I am having trouble with, modulates the gate to maintain a flow rate on the magnetic flow meter.
My problem is, it jumps around from max to min doesn't seem to track properly at all. It's reverse acting. The P parameter seems to track properly, but when I add some I, it tracks the opposite way that I'd expect. I'm not sure if my parameters/ranges are correct.
I'm scaling my setpoint (F16:22) and the process variable (F14:226) from 0 - 16383 before sticking them in the PID. My control variable (output) gets scaled down to 0 - 100. Temporarily, I've limited the output from 0 - 40% to prevent completely draining another process as this wildly swings around.
Unfortunately, this snap shot came when the process was finally shutdown (and I had pulled out most of my hair).
Can anyone help?
Thanks!
I'm having a lot of trouble tuning a PID loop on a SLC 5/05. Can someone tell me if I'm doing something wrong? Please see attachment to this thread.
Basically, I have a gate opens into a wetwell. I am opening the gate to allow flow into the wetwell. The wetwell has a PID loop (that works just fine) that varies the speed of pumps which maintain a wetwell level. What comes in, gets pumped out. After the pumps, there is a magnetic flow meter. The loop I am having trouble with, modulates the gate to maintain a flow rate on the magnetic flow meter.
My problem is, it jumps around from max to min doesn't seem to track properly at all. It's reverse acting. The P parameter seems to track properly, but when I add some I, it tracks the opposite way that I'd expect. I'm not sure if my parameters/ranges are correct.
I'm scaling my setpoint (F16:22) and the process variable (F14:226) from 0 - 16383 before sticking them in the PID. My control variable (output) gets scaled down to 0 - 100. Temporarily, I've limited the output from 0 - 40% to prevent completely draining another process as this wildly swings around.
Unfortunately, this snap shot came when the process was finally shutdown (and I had pulled out most of my hair).
Can anyone help?
Thanks!
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