Adjust Concentration Measurement With Trim Offset And Trim Slope - Emerson Micro Motion Configuration And Use Manual

9.7 Adjust concentration measurement with Trim
Offset and Trim Slope
Trim Offset and Trim Slope adjust the meter's concentration measurement to match a
reference value.
Tip
You can adjust concentration measurement by applying the trim offset only, or by applying both the
trim offset and the trim slope. For most applications, the trim offset is sufficient.
Prerequisites
You must be able to take measurements of your process fluid at two different
concentrations.
You must be able to take a sample of your process fluid at each of these concentrations.
For each sample, you must be able to obtain a laboratory concentration value at line
density and line temperature.
Procedure
1.
2.
3.
4.
5.
6.
Configuration and Use Manual
Collect data for Comparison 1.
a. Take a concentration reading from the meter and record line density and line
temperature.
b. Take a sample of the process fluid at the current concentration.
c. Obtain a laboratory value for concentration at line density and line temperature,
in the units used by the meter.
Collect data for Comparison 2.
a. Change the concentration of your process fluid.
b. Take a concentration reading from the meter and record line density and line
temperature.
c. Take a sample of the process fluid at the current concentration.
d. Obtain a laboratory value for concentration at line density and line temperature,
in the units used by the meter.
Populate the following equation with values from each comparison.
Concentration
Solve for A (slope).
Solve for B (offset), using the calculated slope and one set of values.
Enter the results as the trim slope and the trim offset.
• Using the display: Not available
• Using ProLink III: Device Tools > Configuration > Process Measurement > Concentration
Measurement
(
= A × Concentration
Lab Meter
Measurement support
)
+ B
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