RKI Instruments GX-2009 Manual - Manual (Page 41)

GX-2009 Operator’s Manual Calibration Mode • 36
17. Store the components of the calibration kit in a safe and convenient
place.
Performing a Span Adjustment in ONE CAL
Entering the ONE CAL menu item allows you to perform a span adjustment
on one channel at a time. This feature is useful for situations when you do
not need to calibrate all channels, such as when you are replacing a
sensor.
Perform a span adjustment as part of a calibration after performing a fresh
air adjustment. Performing a span adjustment requires the use of a
calibration kit. The procedure below describes a span adjustment of one
channel using a calibration kit that includes a 4-gas calibration cylinder, a
0.5 LPM (liters per minute) regulator, a calibration adapter plate, and non-
absorbent sample tubing. The standard 4-gas cylinder consists of 50% LEL
methane, 12% oxygen, 25 ppm H2S, 50 ppm CO, and a balance of
nitrogen. If the H2S channel on your GX-2009 is active, then use a 4-gas
cylinder so that you can calibrate all channels when necessary. If the H2S
channel on your GX-2009 is not active, you may use a 3-gas cylinder. The
standard 3-gas cylinder consists of 50% LEL methane, 12% oxygen, 50
ppm CO, and a balance of nitrogen. In the example below, the CH
4
channel’s span is adjusted. See “Parts List” on page 66 for available
calibration kits and calibration kit spare parts.
Calibration cylinders that contain only one target gas may also be used for
single calibration. For channels other than oxygen, RKI Instruments, Inc.
recommends that you use a cylinder that contains a concentration of 10-
50% of the full scale value of the target gas. For example, if you are
calibrating the combustible gas channel, your calibration cylinder should
have a combustible gas concentration between 10% LEL and 50% LEL.
For the oxygen channel, RKI Instruments, Inc. recommends using 100%
nitrogen to perform the adjustment but any concentration between 0%
oxygen (100% nitrogen) and 17% oxygen can be used to make the
adjustment.
NOTE: If your combustible gas channel is calibrated to a gas other than
methane, such as isobutane, use an appropriate gas cylinder to
perform the calibration.
WARNING: Calibrate the GX-2009 in a non-hazardous environment.
1. Before performing a span adjustment, perform a fresh air adjustment as
ONE CAL