COSA Xentaur Xentaur LPDT - Manual (Page 33)

LPDT User’s Manual
page 26
tainer is labeled with the proper values.
5. Calibration Adjustment: In this mode the user can
enter a sensor specific Adjustment Value to improve the
instruments’ accuracy in the range of -50°C to -10°C,
this adjustment has very little or no effect outside this
range. The Calibration Adjustment Value is printed on
the shipping container supplied with the sensor, or may
be derived if the sensor can be exposed to a known ref-
erence.
① Deriving an Adjustment Value: If the adjustment
value for your sensor is not known, contact your repre-
sentative and follow the instructions in paragraph B on
the next page. If the value is not available, then it may
be derived using a manual method, provided that a
moisture calibration lab is available.
The calibration must be done in the range of -25°C to
-20°C (attempting to calibrate outside this range may
cause inaccuracies), the dewpoint must be kept stable
during calibration and it must be measured accurately
by a reference instrument such as a chilled mirror. One
must also note the state of pressure compensation and
turn it on or off as applicable to the reference.
The necessary steps are described below (also refer to
the Set-Up State flow diagram in Appendix B):
a. Make sure that the low attenuation and low dewpoint
are correctly entered for this sensor.
b. SpanCheck™ the sensor.
c. Dry-down the sensor for at least 12 hrs.
d. Expose the sensor to the known dewpoint (-25°C to
-20°C), for a sufficient time (at least 30 min.)
e. Go to the
&$/$'- mode and press the UP button, the
display will show the current value, in the range of -1.99
to +1.99 followed by blinking horizontal lines.