8800CF020SA1N1D1I1M5Q4Q70 model Vortex flow meter has started showing erratic reading suddenly. It was working fine but all of sudden started showing eratic.
Sensor resistance between sensor tip and ground was checked and found ok.
Upstream Downstream valve closed, actual flow is zero(cross checked with other process parameters) but still Flow meter showing 7-8 Te/Hr.
Electronics replaced on doubt basis and all parameters entered in new electronics. Still same problem faced of false reading and huting.
Meter was dropped from flange to inspect shadder bar(Being Pure acetic acid service), it was observed neat and clean. No physical damage/pitting observed.
When meter was dropped and kept on floor, it showed 0 Te/Hr, but when installed in line with no process flow , started showing 7-8 Te/Hr.
Please suggest what could be the cause of such behaviour.
Filtering parameters, LFC cutoff, Low pass filter freq. and all checked and canged as per shadding freq. at normal process flow.