Term Definition
Manual Zero The zero value stored in the transmitter, typically obtained from a zero calibration
procedure. It may also be configured manually. Also called “mechanical zero” or “stored
zero”.
Live Zero The real-time bidirectional mass flow rate with no flow damping or mass flow cutoff
applied. An adaptive damping value is applied only when the mass flow rate changes
dramatically over a very short interval. Unit = configured mass flow measurement unit.
Zero Stability A laboratory-derived value used to calculate the expected accuracy for a sensor. Under
laboratory conditions at zero flow, the average flow rate is expected to fall within the
range defined by the Zero Stability value (0 ± Zero Stability). Each sensor size and model
has a unique Zero Stability value. Statistically, 95% of all data points should fall within the
range defined by the Zero Stability value.
Zero Calibration The procedure used to determine the zero value.
Zero Time The time period over which the Zero Calibration procedure is performed. Unit = seconds.
Field Verification Zero A 3-minute running average of the Live Zero value, calculated by the transmitter. Unit =
configured mass flow measurement unit.
Zero Verification A procedure used to evaluate the stored zero and determine whether or not a field zero
can improve measurement accuracy.
14.4 Set up pressure compensation
Pressure compensation adjusts process measurement to compensate for the pressure effect on the sensor.
The pressure effect is the change in the sensor’s sensitivity to flow and density caused by the difference
between the calibration pressure and the process pressure.
Tip
Not all sensors or applications require pressure compensation. The pressure effect for a specific sensor model
can be found in the product data sheet located at www.emerson.com. If you are uncertain about
implementing pressure compensation, contact customer service.
Prerequisites
You will need the flow factor, density factor, and calibration pressure values for your sensor.
• For the flow factor and density factor, see the product data sheet for your sensor.
• For the calibration pressure, see the calibration sheet for your sensor. If the data is unavailable, use 20 psi
(1.38 bar).
You must be able to supply pressure data to the transmitter.
If you plan to poll an external device, the primary mA Output (Channel A) must be wired to support HART
communications.
If you plan to use the mA Input for pressure data, Channel D must be available for use, and must be wired to
an external pressure device.
Configuration and Use Manual Measurement support
MMI-20025166 March 2019
Configuration and Use Manual 209
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