pulse output in ultrasonic & coriolis flowmeter

[khaledXY]

HI everyone ;

While i was reading a specification of custody transfer system provided by SHELL, something caught my attention that I did not understand, which is that they impose that the primary output of linear custody transfer meters should be pulses (do not use analg or digital), even in ultrasonic or coriolis flowmeter.
I'am asking why this recommandation?

thank you;

 

[RedSnake]

If it is an important signal, for safety reasons in some regard.
It might be a way to ensure that it reads the right signal.
Its harder to manipulate a pulsed signal then a ordinary one too.
Just a guess, though.

Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[IRstuff]

Custody transfer accuracy/verisimilitude involves huge amounts of money exchanging hands, so

https://visaya.solutions/en/qa/pulse-analog-custody-transfer

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[RedSnake]

I get the actual text in the link, I read it two times in English and one in Swedish. ;-)
But it's just a claim no explanation.

Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[IRstuff]

Please refrain from double posting

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[IRstuff]

A-- I think it's simply a recommendation along the lines of your comments that a purely analog transmission runs the risk of corruption and does not provide the accuracy that a digital transmission has. Additionally, there is the issue of timing; the article states that a pulsed measurement is faster and therefore more able to accurately reflect what's happening at any given instant, particularly for custody transfer of moving material in a pipeline.

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[srini1785]

Legal metrology stipulates that repetitive accuracy be maintained within limits of the calibration period. Most meters that are used in off-shore custody transfers (like an unloading tanker) use a Positive displacement meter and the primary output of these meters are pulses. So for a single sweep of two meshing tooth wheels, there is a specific amount (volumetric) of the fluid that is transferred and a single pulse is generated. These pulses are then converted to volume approximation (or mass) by a digital meter. Frankly, no idea why pulses are main signals in indirect meters like ultrasonic or Coriolis.