RKI Instruments GP-01 - Manual (Page 23)

Model GP-01 Operator’s Manual Calibration • 18
Calibration
This section covers the calibration of the Model GP-01. Setting the fresh air
reading is described first followed by setting the span reading. You are also
told what is needed to complete the task and how to assemble the
calibration kit.
WARNING: Use a 0.5 LPM (liters per minute) fixed flow regulator
when calibrating. Using a different flow rate may
adversely affect the accuracy of the calibration.
Calibration Frequency
If the GP-01 passes the response test described in “Start Up” on page 9
and does not require calibration after startup, the unit should still be
calibrated periodically. The optimum frequency of calibration depends
heavily on how the GP-01 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 develop a calibration schedule tailored to your application that takes the
response test and required calibration resulting from this test into account.
Setting the Fresh Air Reading
You will need to set the fresh air reading first before setting the span
reading.
1. Find a fresh air environment of normal oxygen content (20.9%) that is
free of toxic or combustible gases.
2. With the unit on and in Measuring Mode, press and hold the AIR button.
The LCD displays “hold” prompting you to hold the AIR button.
3. Release the AIR button when the LCD displays “AdJ”. The unit will set
the reading to 0% LEL and return to Measuring Mode.
Setting the Span Reading
This section tells you how to set the span reading using Calibration Mode.
Preparation
Set the fresh air reading as described in “Setting the Fresh Air Reading”.
You will also need the supplies listed below. A calibration kit is available
from RKI Instruments, Inc. for the Model GP-01 for this purpose (see “Parts
List”).