Honeywell SMV 3000 user manual Output Conformity Background, About Square Root Output

6.6 DPConf Configuration - PV1, Continued

Output Conformity

Background

Select the output form for differential pressure (PV1) variable to represent one of these selections. Note that calculated flow rate process variable (PV4) includes a square root operation and it is not affected by this selection.

•LINEARd

•SQUARE ROOT

d Factory setting.

The PV1 output is normally set for a straight linear calculation since square root is performed for PV4. However, you can select the transmitter’s PV1 output to represent a square root calculation for flow measurement. Thus, we refer to the linear or the square root selection as the output conformity or the output form for PV1.

About Square Root Output

For SMV 3000 transmitters measuring the pressure drop across a primary element, the flow rate is directly proportional to the square root of the differential pressure (PV1) input. The PV1output value is automatically converted to equal percent of root DP when PV1 output conformity is configured as square root.

You can use these formulas to manually calculate the percent of flow for comparison purposes.

	• 100 = %P
Where,	∆ P	= Differential pressure input in engineering units
	Span	= Transmitter’s measurement span (URV – LRV)
	%P	= Pressure input in percent of span
Therefore,	%P	• 100 = % Flow
	100

And, you can use this formula to determine the corresponding current output in milliamperes direct current.

(% Flow • 16) + 4 = mA dc Output

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