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Postrequisites
If the reported mass flow rate is not accurate:
• Check the characterization parameters.
• Review the troubleshooting suggestions for flow measurement issues. See
Section 10.3.
2.6 Verify the zero
Verifying the zero helps you determine if the stored zero value is appropriate to your
installation, or if a field zero can improve measurement accuracy.
The zero verification procedure analyzes the Live Zero value under conditions of zero flow,
and compares it to the Zero Stability range for the sensor. If the average Live Zero value is
within a reasonable range, the zero value stored in the transmitter is valid. Performing a
field calibration will not improve measurement accuracy.
2.6.1 Verify the zero using ProLink II
Verifying the zero helps you determine if the stored zero value is appropriate to your
installation, or if a field zero can improve measurement accuracy.
Important
In most cases, the factory zero is more accurate than the field zero. Do not zero the flowmeter unless
one of the following is true:
• The zero is required by site procedures.
• The stored zero value fails the zero verification procedure.
Prerequisites
ProLink II v2.94 or later
Important
Do not verify the zero or zero the flowmeter if a high-severity alarm is active. Correct the problem,
then verify the zero or zero the flowmeter. You may verify the zero or zero the flowmeter if a low-
severity alarm is active.
Procedure
1. Prepare the flowmeter:
a. Allow the flowmeter to warm up for at least 20 minutes after applying power.
b. Run the process fluid through the sensor until the sensor temperature reaches
the normal process operating temperature.
c. Stop flow through the sensor by shutting the downstream valve, and then the
upstream valve if available.
Quick start
Configuration and Use Manual 11