13 Measurement support
13.1 Adjust temperature measurement with
Temperature Offset or Temperature Slope
You can adjust the sample temperature measurement by modifying the value for Temperature Offset or
Temperature Slope. The measured temperature value is always multiplied by the temperature slope. The
temperature offset is always added to the result.
Micro Motion does not recommend adjusting the sample temperature because the RTD sensor is located
inside the measurement chamber. Typically, the sample temperature is different from the process
temperature, and attempting to adjust this variable on the field can cause significant accuracy errors.
Prerequisites
You will need an external temperature measurement method that is highly accurate.
Ensure that your process is stable during the sampling procedure. Minimize variation in density, temperature,
flow rate, and fluid composition. Minimize aeration.
Meter-specific temperature calibration factors are determined at the factory. These values are available on
the meter tag. Temperature Offset and Temperature Slope are applied after the temperature calibration
factors.
The default value for Temperature Offset is 0. The default value for Temperature Slope is 1.0. Accordingly,
the default values have no effect on the reported temperature value.
Note
Temperature offset and temperature slope are applied only to temperature data from the on-board
temperature sensors (internal RTD). External temperature data is not adjusted.
Tip
Although you can set Temperature Offset or Temperature Slope manually, the temperature calibration
procedure will generate a pair of offset and slope values that are more accurate for the individual meter.
However, temperature calibration can be difficult. Consult Micro Motion before performing a temperature
calibration.
Procedure
1. Take a temperature reading from the meter.
2. Immediately after the previous step, take a sample from a location as close to the meter as possible.
3. Using the external measurement method, measure the temperature of the sample.
4. Use the following equation to calculate an appropriate value for Temperature Offset or Temperature
Slope.
t
Sample=TemperatureSlopex(ρSample + TemperatureOffset
Tip
In most cases, you will set only one parameter. Follow the guidelines established for your site.
Configuration and Use Manual Measurement support
MMI-20020954 March 2021
Configuration and Use Manual 111
To Next Page