Section 6: Meter operation

Reference, Installation, and Operations Manual

June 2013

3-9000-743 Rev S

 

 

Equation 6-9 Wet-calibration gas flow velocityVWetCal = WetCalFunction(VDryCal)

where

 

 

VWetCal

=

wet-calibration gas flow velocity (m/s) (AvgFlow)

VDryCal

=

dry-calibration gas flow velocity (m/s) (DryCalVel)

WetCalFunction(x)

=

selected wet calibration function
Piece-wise linearization

If the 12-point piece-wise linearization (PWL) wet calibration method is selected, then the dry- calibration gas flow velocity is calculated as shown in Equation 6-10.

The inputs to the 12-point piece-wise linearization are the (up to) 12 pairs of volumetric flow rate and meter factor for each flow direction ([FwdFlwRt1, FwdMtrFctr1], ..., [FwdFlwRt12, FwdMtrFctr12] for forward flow; [RevFlwRt1, RevMtrFctr1], ..., [RevFlwRt12, RevMtrFctr12] for reverse flow). Refer to Section 5.7.3 for information on using the Daniel MeterLink Field Setup Wizard for entering these data point values.

The input flow rates should be entered in descending order (highest first) with their corresponding meter factors. If these are entered in the wrong order, the meter will still work but the accuracy may be affected. The meter will not accept negative values, so only positive values should be entered for both forward and reverse flow rates. If fewer than 12 points are to be used, the unused flow rate and meter factor pairs should be set to 0 and 1 respectively.

Equation 6-10 Wet Calibration - 12-Point Piece-wise linearizationVWetCal = VDryCal LinearMeterFctr

where

 

 

VWetCal

=

wet-calibration gas flow velocity (m/s) (AvgFlow)

VDryCal

=

dry-calibration gas flow velocity (m/s) (DryCalVel)
LinearMeterFctr

=

linear meter factor (dimensionless) (LinearMeterFctr)

The linear meter factor is determined by the PWL inputs, the flow direction, and the dry- calibration gas flow velocity.

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Calibration