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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.
d. Verify that the sensor is blocked in, that flow has stopped, and that the sensor is
completely full of process fluid.
2. Choose Device Tools > Device Calibration > Zero Verification and Calibration > Verify Zero and
wait until the procedure completes.
3. If the zero verification procedure fails:
a. Confirm that the sensor is completely blocked in, that flow has stopped, and that
the sensor is completely full of process fluid.
b. Verify that the process fluid is not flashing or condensing, and that it does not
contain particles that can settle out.
c. Repeat the zero verification procedure.
d. If it fails again, zero the flowmeter.
For instructions on zeroing the flowmeter, see Section 9.3.
Postrequisites
Restore normal flow through the sensor by opening the valves.
2.6.3 Terminology used with zero verification and zero
calibration
Terminology used with zero verification and zero calibrationTable 2-2:
Term Definition
Zero In general, the offset required to synchronize the left pickoff and the right pickoff under
conditions of zero flow. Unit = microseconds.
Factory Zero The zero value obtained at the factory, under laboratory conditions.
Field Zero The zero value obtained by performing a zero calibration outside the factory.
Prior Zero The zero value stored in the transmitter at the time a field zero calibration is begun. May
be the factory zero or a previous field zero.
Manual Zero The zero value stored in the transmitter, typically obtained from a zero calibration proce-
dure. It may also be configured manually. Also called “mechanical zero” or “stored zero.”
Quick start
Configuration and Use Manual 15