RKI Instruments GX-2009 Manual - Manual (Page 33)

GX-2009 Operator’s Manual Calibration Mode • 28
Calibration Mode
This section describes the GX-2009 in Calibration Mode. In Calibration
Mode, you can move through a menu of screens to do the following:
• Set the date and time
• Perform a fresh air adjustment (part of a calibration)
• Perform a span adjustment on all channels simultaneously (part of a
calibration)
• Perform a span adjustment on one channel at a time (part of a
calibration)
• Perform a bump test (if Bump Test Function is set to On using the
GX-2009 User Setup Program)
• Discharge the batteries with the REFRESH function
NOTE: You can set the GX-2009 to alert you during the startup sequence
when calibration or bump testing is due with the GX-2009 User
Setup Program. See the GX-2009 User Setup Program
Operator’s Manual for information on setting the Cal. Limit
Display and Bump Limit Display parameters.
CAUTION: BEFORE EACH DAY’S USAGE SENSITIVITY IN THE
% LEL RANGE MUST BE TESTED ON A KNOWN
CONCENTRATION OF THE COMBUSTIBLE TARGET GAS,
TYPICALLY METHANE, EQUIVALENT TO 25 - 50% OF FULL
SCALE CONCENTRATION (The %LEL full scale is
100% LEL). ACCURACY MUST BE WITHIN -0 to + 20% OF
ACTUAL. ACCURACY MAY BE CORRECTED BY
FOLLOWING THE CALIBRATION INSTRUCTIONS FOR THE
COMBUSTIBLE CHANNEL BELOW.
If the combustible channel passes the above response test and does not
require calibration, the unit should still be calibrated periodically. The
optimum frequency of calibration depends heavily on how the GX-2009 is
used. For example, instruments used daily may need to be calibrated
weekly or monthly, while instruments that are used only a few times a year
may need to be calibrated before each use. Typical calibration frequencies
range from monthly to quarterly. Make sure to perform the combustible
channel response test as described above and make sure to develop a
calibration schedule tailored to your application that takes this test and
required calibration resulting from this test into account.