Piecewise Linearization (Pwl) For Calibrating Gas Meters; Zero The Meter - Emerson Micro Motion 1700 Configuration And Use Manual

Measurement support
9.4 Piecewise linearization (PWL) for calibrating
gas meters
Piecewise linearization (PWL) can linearize the measurements of flow meters for greater
accuracy in order to measure gas over a wide range of flow rates. PWL does not apply when
measuring liquid flow. When better accuracy is required over the published gas
measurement specifications, an Emerson-approved independent gas laboratory can
calibrate gas up to 10 PWL adjustment points.
PWL configuration and calibration information is not available through HART.
For more information, see the white paper, The Practical Application of Multi‐Point Piecewise
Linear Interpolation (PWL) and Other Developing Trends with Coriolis Meters for Natural Gas
Custody Transfer Applications, available at www.emerson.com.
The PWL feature is available in ProLink III, so you can view the points that are stored and
capture them in the uploaded and downloaded configuration files.
9.5

Zero the meter

Zeroing the meter establishes a baseline for process measurement by analyzing the
sensor's output when there is no flow through the sensor tubes.
Prerequisites
Verify the zero and prepare the meter using the procedures in
Procedure
Zero the meter.
Tool
Display
ProLink III
Field Communicator
If necessary, modify Zero Time. Zero Time controls the amount of time the transmitter
takes to determine its zero-flow reference point. The default Zero Time is 20 seconds. For
most applications, the default Zero Time is appropriate.
Postrequisites
Restore normal flow through the sensor by opening the valves. Verify that the sensor tubes
are full.
Need help?
134
Path
OFFLINE MAINT > ZERO > CAL ZERO > CAL/YES?
To restore the zero value set at the factory: OFFLINE MAINT > ZERO > RESTORE ZERO > RE-
STORE/YES? This function requires the enhanced core processor.
Device Tools > Calibration > Zero Verification and Calibration > Calibrate Zero
Service Tools > Maintenance > Zero Calibration > Perform Auto Zero
If the zero fails:
Micro Motion Model 1700 Transmitters with Analog Outputs
Section 2.6.