I noticed that the LLCV is railing at its top value, 100% open, it can't open no more. This is a known issue, but it appears as if the valve is reaching 100% sooner than expected, meaning when the tank is almost half full. First, I'm going to try a re-zero the LLCV actuator and await for the results. First attachment is a 2 day plot of LLCV railing today and yesterday. The second plot is a 3 year history looking at the tank level and the LLCV, it rails at 100% a few times.
BURT restore? PID tuning ok? CP2 @ LLO PID parameters attached for comparison.
Thanks Jon. However, this system has a known issue, it turns out that the liquid level control valve is not suitable for the job, that is the reason why it reaches 100% sooner than later, but it appears as if something slip, now it reaches 100% at a higher level, this is the reason why I want to re-zero the actuator.
Attached is the Fill Control for CP7 The issue was mentioned here for the first time aLOG 4761, but I never found out who discovered this is only briefly mentioned by Kyle. Another entry on aLOG 59841.
Dirty solution of solving the issue with the LLCV getting railed at 100% open, we used the bypass valve, opened it up by 1/8 of a turn and that did the job. Not a single shot, but eventually we settle on that turn number. PID took over and managed to settle around to 92% open for the LLCV. Today we received a load for the tank for CP7. We are still going to calibrate the actuator.
