RKI Instruments Digester Gas Monitor - Manual (Page 67)

Digester Gas Monitor Operator’s Manual Overview • 61
Chapter 8: Calibration Mode
Overview
This chapter describes how to calibrate the Digester Gas Monitor’s active channels using
Calibration Mode. In Calibration Mode, you can:
• Set the calibration timeout.
• Perform a fresh air adjust on selected channels.
• Perform a gas adjust on selected channels.
• View Max Spans.
Table 10 below briefly describes the four operations that can be performed in Calibration
Mode. A more detailed description of each operation is given later in this chapter.
Calibration Frequency
Although there is no particular calibration frequency that is correct for all applications, a
calibration frequency of every month is adequate for most Digester Gas Monitor
applications. Unless experience in a particular application dictates otherwise, RKI
Instruments, Inc. recommends a calibration frequency of every 3 months.
If an application is not very demanding, for example detection in a clean, temperature
controlled environment where a combustible or toxic gas is not normally present, and
calibration adjustments are minimal at calibration, then a calibration frequency of every 6
months may be adequate.
If an application is very demanding, for example if a combustible or toxic gas is present
often and in significant concentrations or the environment is not well controlled, then more
frequent calibration than every month may be necessary.
Table 10: Calibration Mode Functions
Operation Description
SET CAL TIMEOUT The calibration timeout sets the amount of time after the
last button push while in Calibration Mode that the
Digester Gas Monitor will wait before automatically
returning to Standby Mode.
PERFORM AIR ADJUST This operation allows you to set the fresh air reading of
the selected channel(s) to zero (20.9% for the oxygen
channel).
PERFORM GAS ADJUST This operation allows you to set the response reading of
the selected channels with calibration gas.
VIEW MAX SPANS This operation gives a measure of how much gas
response adjustment remains on a direct connect type
channel by allowing you to view the maximum possible
adjustment on gas during the most recent calibration for
each channel.