RKI Instruments M2A - Manual (Page 46)

41 M2A Transmitter Operator’s Manual
Calibration Frequency
Some M2As have IR (infrared) type detectors, such as an M2A for CO
2
or an LEL M2A with an IR
detector. Most of the M2As do not have an IR detector. For example, an H
2
S M2A has an
electrochemical detector and some of the combustible M2As use catalytic detectors. The M2As that
use IR detectors typically need less frequent calibration as is discussed below. See Table 1, “M2A
Specifications,” on page 2 to see which M2As are IR versions.
Although there is no particular calibration frequency that is correct for all applications, a calibration
frequency of every 3 to 6 months for M2As that do not have an IR detector and every 6 to 12
months for M2As that have an IR detector is adequate for most M2A applications. Unless
experience in a particular application dictates otherwise, RKI Instruments, Inc. recommends a
calibration frequency of every 3 months for M2As that do not have an IR detector and every 6
months for M2As that have an IR detector.
If an application is not very demanding, for example detection in a clean, temperature controlled
environment where the toxic or combustible target gas is not normally present, and calibration
adjustments are minimal at calibration, then a calibration frequency of every 6 months for a non-IR
M2A or 12 months for an IR M2A is 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 3 months for a non-IR M2A or every 6 months for an IR M2A may be
necessary. For combustible gas detection with an M2A that uses a catalytic detector, if potential
catalyst poisons are known or likely to be present, more frequent calibration than every 3 months
will be necessary.