Filter
Top Products
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.
9.3.1 Zero the flowmeter using the zero button
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
Using the zero button, you cannot change the value of Zero Time. 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 use a different method to zero the flowmeter.
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. Using a fine-pointed tool, press the zero button on the face of the transmitter, and
hold it down until the status LED begins to flash yellow.
The status LED flashes yellow while the procedure is in progress. At the end of the
procedure:
• If the zero procedure was successful, the status LED shows solid green or solid
yellow.
• If the zero procedure failed, the status LED shows solid red.
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 123