Instruments failing after power failure

[mmd604]

I am doing maintenance on a older line and we have had a power failures and a instrument failed.  The instrument in question Micro motion corelios apparently this has happen before with another instrument on another power failure.  Anybody out there have any experiences like this and if you did any remedies

[drforsythe]

We use Micro Motion flow meters throughout our plant.  They are great meters.  We have had issues with the old (>20 years old) devices after power failures.  I don't recall which model the old ones are, but we cannot even get them repaired reliably.  We have been systematically replacing the old units with the 5700 series transmitters.  They work with some of the old flow sensors, depending on the number of wires in the sensor.  I highly recommend contacting Emerson to find out who your local Micro Motion salesperson is.  They are really good to work with (at least in my experience).

[NevergoldMel]

Twenty years is a good life for a flow meter.

[DanW]

I'd guess that the DC power supply probably failed taking out the meter's electronics.   

In general, Coriolis meters are AC powered.   An internal DC power supply provides power for running the components.   DC power supplies have finite life spans.   When capacitors fail, they fail.  

If it were a case of electrical surges or brown-outs causing the failure, then either a ferro-resonant transformer (Sola) or a battery powered UPS could condition the AC to the meter.

From the 1980's forward, the era of field repairable instrumentation disappeared with the adoption of microelectronics.  Vendors stopped providing schematics, parts lists, or service manuals.   Many users don't have anyone that can troubleshoot and do component level repair either.

I/O boards, comm modules and digital displays might sometimes be available as replacement assemblies for the converter/transmitter electronics end of the flow meter, depending on the manufacturer.  10 years I remember being surprised to find a company that would re-wire the coils in the larger magmeter tubes, but I suspect coriolis tubes are unrepairable.