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Amplifier 2700 FF total mass update rate

We have just replaced and old Micromotion massflow meter with a new one. The old one did send the flow rate to DeltaV as a frequency and the mass integration was done in DeltaV. The new meter with amplifier 2700 is connected to DeltaV with Foundation Fieldbus protocol. The idea was to let the amplifier to do the mass integration and to read to DeltaV the totalized mass. Sounds simple, but real life is different. The amplifier is equipped with a display, so I can se the total mass counter incrementing. BUT, the mass is not incrementing steadily! There can be breaks as long as 5  seconds. After that time the totalizer will jump to the rigt value, so that is OK, but we are running a batch process and the dosing must be stopped promptly at a right total mass.

I used ProLink III also to store data once per second during a test. In the data file I can see that the total mass is not updated in the worst case for 9 seconds! The total mass display in DeltaV stops incrementing also, so the issue should not be DeltaV but the amplifier itself.

 

Ofcourse there is a workaround to read the flow rate to DeltaV and integrate the mass from the flow rate, but I do not trust DeltaV integrators...

The same principle will be used in 3 other massflow meters, of which one is already at our site.It could be difficult to send one back as "not needed".

Does anybody have same kind of experience? Do we have a wrong setting somewhere in the amplifier? HELP!

Best Regards,

Tom

1 Reply

  • I reply now to my own question, as we have managed to find out the root cause. From customer point of view amplifier software version 8 is faulty. Emerson installed version 7 in the amplifier and we did the same on DeltaV FF-side and now we get a pretty stable 1 Hz update rate of total mass both in amplifier display and on DeltaV display. That is good enough for our application and we have repeatble calibartion results. Who knows if there will soon be a version 9 where the bug (?) is fixed, or is this the future that Emerson makes it on purpose impossible to use the total mass for accure doising applications?