Hello,
I've recently installed a ultrasonic level transducer to control a VFD pumping out of a vat. The vat is "slug" filled by other pumps. The purpose of the vat is to act as a balance tank.
I've simply programmed the drive in analog control mode. Vat empty is minimum speed, vat full is max speed. It works fairly good and really smooths out the process, however I am dealing with varying head pressure against the pump. Filtration efficiency and the level in the output tank are placing varying head pressure on the pump, and as such, once pump speed slows to a certain RPM, it will no longer actually pump. Given clean filters and an empty output tank, the vat will empty almost completely at a much lower pump RPM, full output tank and higher filter back pressure requires higher pump RPM to maintain flow.
I've programmed the level transducer (Flowline EchoPod) to read 0 mA at 0" in vat, 20 mA at 46.6" (vat over full).
So, I'm wondering if a PID loop would be a better way to treat this scenario? I've done some trial settings, but can't seem to get it to work like I've envisioned it in my head.
Am I correct that this be a reverse acting (cooling) PID loop?
Would a PID loop be appropriate in this application?
Thanks!
I've recently installed a ultrasonic level transducer to control a VFD pumping out of a vat. The vat is "slug" filled by other pumps. The purpose of the vat is to act as a balance tank.
I've simply programmed the drive in analog control mode. Vat empty is minimum speed, vat full is max speed. It works fairly good and really smooths out the process, however I am dealing with varying head pressure against the pump. Filtration efficiency and the level in the output tank are placing varying head pressure on the pump, and as such, once pump speed slows to a certain RPM, it will no longer actually pump. Given clean filters and an empty output tank, the vat will empty almost completely at a much lower pump RPM, full output tank and higher filter back pressure requires higher pump RPM to maintain flow.
I've programmed the level transducer (Flowline EchoPod) to read 0 mA at 0" in vat, 20 mA at 46.6" (vat over full).
So, I'm wondering if a PID loop would be a better way to treat this scenario? I've done some trial settings, but can't seem to get it to work like I've envisioned it in my head.
Am I correct that this be a reverse acting (cooling) PID loop?
Would a PID loop be appropriate in this application?
Thanks!