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HMRC internal manual

Oils Technical Manual

HM Revenue & Customs
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Flow Computers: Turbine pulses, recording of totals and configuration

Turbine pulses

The computer monitors two pulse streams from the turbine meter. The number of failedpulses can be monitored and an alarm is raised if the occurrence reaches a defined limit.A flow computer requires the number of pulses per gross m3 to establish the productvolume.

Additionally, a flow computer may make available the pulse signal for connection toanother flow computer controlling a proving loop or master meter.

Recording of totals

It can be expected that the manufacturer will have addressed faults in the meterelectronics causing the loss of totaliser values. It is common to find that each total isstored 3 times and the system monitors the agreement of the totals and raises an alarm ifthey differ.

The ‘End of Day’ for totaliser purposes is programmed by the user and triggeredby the computers internal time clock.

Some flow computers have the ability to drive mechanical counters.

Configuration of a flow computer

The accuracy of the arithmetic calculations of the volumes reported by the flowcomputer, are dependant upon:

  • the accuracy of the parameters established when a flow computer is first commissioned;
  • the controls imposed to ensure the periodic checking of the parameters and the controls on the amendment of the parameters; and
  • the control of the parameters passed to the computer from other systems. Critical parameters are the data used in the Standard Temperature Accounting (STA) calculation and the density.