Crystal DataLoggerXP Digital Pressure Gauge Software - Manual (Page 40)

Support  38
XP2i Operation Manual
—
caLIBratIon
factory adjustment
If adjustment is required, we recommend returning the unit to the factory. Factory service offers benefits you won’t find anywhere else. We have the facilities
to test your gauge at a variety of temperatures utilizing NIST traceable standards in our A2LA accredited laboratory, resulting in calibration certificates that
provide performance data over temperature. Furthermore, upgrades may be available to add or enhance operating features. We designed the product to last,
and we support it so that you can get the most from your investment.
calibration frequency
Under normal operating conditions, we recommend the XP2i be calibrated on an annual basis. Your quality system may require more or less frequent calibra-
tion, or your experience with the gauge, or operating environment may suggest longer or shorter intervals.
Although we prefer that you return the XP2i to Crystal Engineering for calibration, ordinary recertification and/or adjustments may be performed by any
qualified personnel with appropriate training and equipment.
span factor
There are no internal potentiometers. The XP2i contains a “span” factor, set to approximately 1 (as shipped from the factory). As components age this may
need to be changed to a value slightly higher or lower, to slightly increase or decrease all readings. This adjustment can be made with or without a computer
(see
configXP configuration software ).
X span factor adjustment
Note: The following instructions are ONLY intended for such qualified personnel with appropriate test equipment. We recommend that the calibration stan-
dards used have a minimum rated accuracy of 0.025% of reading, or equivalent in terms of percent of full scale. This level of accuracy requires the use
of piston (deadweight) gauges or very high performance pressure controllers.
“Zero” the XP2i, then record displayed pressure for two or more pressure points. Determine if the XP2i would benefit from an overall increase or decrease of
the indicated pressures.
To change the span factor from the keypad, turn off the XP2i, then press the
(
on/off
)
,
(
units
)
, and
(
peak
)
buttons simultaneously. The firmware version will
be briefly displayed, followed by the word cal , followed by the actual span value. The span factor may be adjusted by pressing either the
(
units
)
or
(
peak
)
button to increase or decrease the value, respectively. The value changes in 0.0001 increments. Press the
(
zero
)
button to store the new value in memory, or
the
(
on/off
)
button to cancel the change.
For absolute XP2is, it is possible to correct for long term drift using a second calibration factor, zero value offset. ConfigXP and a barometric reference with
accuracy of 0.1 psi or better is required to perform the calibration. To calibrate the zero offset, clear the zero as described earlier in this manual by pressing and
holding the
(
zero
)
button until ( ) appears. Once cleared, subtract the displayed pressure from barometric pressure, add this difference to any existing
zero value offset in ConfigXP, and update the gauge (new value = barometric – displayed + existing). For example, if the displayed value is 14.5 psi, barometric
pressure is 14.7 psi, and the existing zero value offset in ConfigXP is 0.1 psi, the new zero value offset would be 0.3 psi (14.7 - 14.5 + 0.1 = 0.3).
The span factor and zero value offset can be viewed and set directly by ConfigXP. Span factor adjustment through the keypad
can be disabled by ConfigXP through the disable span factor feature or by password protecting the XP2i . XP