Procedure
1. 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.
2. 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.
3. Populate the following equation with values from each comparison.
Concentration
Lab
= A × Concentration
Meter
+ B
4. Solve for A (slope).
5. Solve for B (offset), using the calculated slope and one set of values.
6. Enter the results as the trim slope and the trim offset.
• Using ProLink III: Choose Device Tools → Configuration → Process Measurement → Concentration
Measurement, set Matrix Being Configured to your matrix, and enter Trim Slope and Trim Offset.
• Using a field communicator: Choose Device Settings → Process Configuration → Optional Setup
→ Concentration Measurement → Configure Matrix and set Matrix Being Configured to your
matrix. Then choose Device Settings → Process Configuration → Optional Setup → Concentration
Measurement → Trim CM Process Variables and enter Concentration Slope and Concentration
Offset.
7. Take another concentration reading from the meter, and compare it to the laboratory value.
• If the two values are acceptably close, the trim is complete.
• If the two values are not acceptably close, repeat this procedure.
Calculating the trim slope and the trim offset
Comparison 1
Laboratory value 50.00%
Meter value 49.98%
Comparison 2 Laboratory value 16.00%
Meter value 15.99%
Populate the equations:
50 = A × 49.98 + B
16 = A × 15.99 + B
Solve for A:
50.00 − 16.00 = 34.00
49.98 − 15.99 = 39.99
34 = A × 33.99
Measurement support Configuration and Use Manual
May2024 MS-00809-0200-1600
158 Emerson.com
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