Calibrating Against A Referee - Grab Sample - Emerson Rosemount 225 Reference Manual

Calibration
August 2018
Results
Figure 3-4
Figure 3-4: Calibration with a referee instrument example
3.4

Calibrating against a Referee - Grab Sample

This method is useful when calibration against a standard is impractical or when in-process
calibration is not feasible, because the sample is hot, corrosive, or dirty, making handling
the waste stream from the referee sensor difficult.
Procedure
1. Take a sample of the process liquid.
2. Connect the process and referee sensors.
22
shows the arrangement.
Take the sample from a point as close to the process sensor as possible. Be sure the
sample is representative of what the sensor is measuring. If possible, adjust the
conductivity of the process liquid so that it is near the midpoint of the operating
range. If that is not possible, adjust the conductivity so that it is at least 5000
µS/cm.
Keep temperature compensation with the transmitter turned on. Confirm that the
temperature measurements in both process and referee instruments are accurate,
ideally to within ±0.5 °C.
Reference Manual
00809-0100-3225
Reference Manual