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9.3.1 Zero the flowmeter using the display (standard option)
Zeroing the flowmeter establishes a baseline for process measurement by analyzing the
sensor's output when there is no flow through the sensor tubes.
Restriction
You cannot change the Zero Time setting from the display. The current setting of Zero Time will be
applied to the zero procedure. The default value is 20 seconds. If you need to change Zero Time, you
must make a connection to the transmitter from a communications tool such as ProLink II.
Prerequisites
Assign the following as display variables:
• Live Zero or Field Verification Zero
• Drive Gain
• Temperature
• Density
See Section 5.1.2 for assistance.
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.
e. Observe the drive gain, temperature, and density readings. If they are stable,
check the Live Zero or Field Verification Zero value. If the average value is close to 0,
you should not need to zero the flowmeter.
2. Navigate to OFFLINE MAINT > ZERO > CAL ZERO and select CAL/YES?.
Dots traverse the display while flowmeter zero is in progress.
3. Read the zero result on the display.
The display reports CAL PASS if the zero was successful, or CAL FAIL if it was not.
Postrequisites
Restore normal flow through the sensor by opening the valves.
Need help? If the zero fails:
• Ensure that there is no flow through the sensor, then retry.
• Remove or reduce sources of electromechanical noise, then retry.
Measurement support
Configuration and Use Manual 153