A customer had a pump coupling disintegrate recently and the mechanical contractor that fixed it told him that his VFD is hunting and that will shorten the life of though coupler.
I stopped out and checked my loop and its not hunting at all measuring voltage at the DX9100 and at the drive. The drive does however keep saying "Up" and "Down" and the frequency varies by about +/- 0.4Hz. Occasionaly it will say "constant" but not often.
I could just tell the customer that the coupling lasted over 6 years and failure could be caused by minor mis-alignment as the speed varience is very small but I would rather make the VFD stop hunting around. We have not seen this type of drive very often so i'm not sure what to adjust.
Specifics are that its a Model # L-300P-150HBRM / MFG.# 15DFT16642 10049
I'm thinking there is some type of noise my meter can not read on the 0-10vdc input to the drive and I have maxed out parameter A016 which says its and input filter but it did not affect it at all. None of the other setting in the book sound like they would fix this so i'm hoping one of you peoples knows