Xylem EXO Series User Manual page 66

Calibration
5.1
Basic
EXO sensors (except temperature) require periodic calibration to assure high performance. Calibration
procedures follow the same basic steps with slight variations for particular parameters. Conduct calibrations
in a temperature-controlled lab.
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Matching units
Click the Start Calibration button. This action initiates the probe's calibration in the standard; initially the
data reported will be unstable and then they will move to stable readings. Click the Graph Data button to
compare the pre-cal and post-cal values in graph form. Users should confirm that the value is within their
acceptable margin of error. Once readings are stable, click Apply to accept this calibration point. Repeat the
process for each calibration point. Click Complete when all points have been calibrated.
A calibration summary appears with a QC score. View, export, and/or print the calibration worksheet. If a
calibration error appears, repeat the calibration procedure.
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Calibration set-up
For accurate results, thoroughly rinse the EXO calibration cup
with water, and then rinse with a small amount of the calibration
standard for the sensor you are going to calibrate. Discard the
rinse standard, then refill the calibration cup with fresh calibration
standard. Fill the cup to approximately the first line with a full
sensor payload or the second line with small sensor payload.
Volumes will vary, just make certain that the sensor is submerged.
Be careful to avoid cross-contamination with other standards.
Begin with a clean, dry probe installed on the EXO sonde. Install
the sonde guard over the probe(s), and then immerse the probe(s)
in the standard and tighten the calibration cup onto the EXO
sonde. We recommend using one sonde guard for calibration
procedures only, and another sonde guard for field deployments.
This ensures a greater degree of cleanliness and accuracy for the
guard used in the calibration procedure.
Basic calibration in KOR software
Go the Calibrate menu in KOR software. This menu's appearance
will vary depending on the sensors installed in the sonde. Select
the sensor you are going to calibrate from the list. Next select
the parameter for the sensor you are going to calibrate. Some
sensors have only one parameter option, while other sensors have
multiple options.
In the next menu, select a 1-, 2-, or 3-point calibration, depending
on your sensor. Enter the value of the standard you are using.
Check that the value you enter is correct and its units match
the units at the top of the menu (e.g., microSiemens versus
milliSiemens). You may also enter optional information for type
of standard, manufacturer of standard, and lot number.