Measurement Performance

10.5.1Preparing for zero

To prepare for the zero procedure:

1.Apply power to the flowmeter. Allow the flowmeter to warm up for approximately 20 minutes.

2.Run the process fluid through the sensor until the sensor temperature reaches the normal process operating temperature.

3.Close the shutoff valve downstream from the sensor.

4.Ensure that the sensor is completely filled with fluid.

5.Ensure that the process flow has completely stopped.

CAUTION

If fluid is flowing through the sensor during zero calibration, the calibration may be inaccurate, resulting in inaccurate process measurement.

To improve the sensor zero calibration and measurement accuracy, ensure that process flow through the sensor has completely stopped.

10.5.2Zero procedure

To zero the flowmeter:

Using the zero button, see Figure 10-4.

Using the display menu, see Figure 10-5.For a complete illustration of the display zero menu, see Figure B-7.

Using ProLink II, see Figure 10-6.

Using a DeviceNet tool, see Figure 10-7.

Note the following:

If the transmitter was ordered with a display:

-The zero button is not available.

-If the off-line menu has been disabled, you will not be able to zero the transmitter with the display. For information about enabling and disabling the off-line menu, see Section 8.9.3.

-You cannot change the zero time with the display. If you need to change the zero time, you must use ProLink II or a DeviceNet tool.

If the transmitter was ordered without a display, the zero button is available.

-You cannot change the zero time with the zero button. If you need to change the zero time, you must use ProLink II or a DeviceNet tool.

-The zero button is located on the user interface board, beneath the transmitter housing cover (see Figure 3-1). For instructions on removing the transmitter housing cover, see Section 3.3.

-To press the zero button, use a fine-pointed object that will fit into the opening (0.14 in or 3.5 mm). Hold the button down until the status LED on the user interface module begins to flash yellow.

During the zero procedure, the status LED on the user interface module flashes yellow.

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Emerson Process Management 2400S manual Preparing for zero, Zero procedure