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© 2021 All rights reserved. Data subject to change without notice.
LPT - Operation Manual
Rev. E | 2021.03
8 CALIBRATION
8.1 Calibration Specifi cations
8.1.1 Gas
Calibration span gases should have at least ± 5% accuracy and have a current date stamp. Gas
generators should have a current dated cell installed. Service personnel should fl ow zero emissions
air or 20.9% volume O
2
(scrubbed of hydrocarbons) before attempting to null adjust toxic gas
sensors. In some cases N
2
can be substituted for zero air. Contact CETCI for clarifi cation.
Every LPT transmitter is calibrated in a chamber by true diff usion method prior to leaving our
facility. This method more closely emulates actual “real world” conditions. Field calibration
using gas cylinder, regulator and hose directing span gas into the sensor may result in slightly
higher readings. It is important to note that the type of gas mixture, how old the gas is and what
temperature it has been stored at will also aff ect repeatability during fi eld calibration.
NOTE:
Oxygen sensors require 99.99% Nitrogen (N
2
) for a true zero and span is done fi rst, followed
by zeroing. Refer to Section
8.3 Calibrating an Oxygen Sensor.
8.1.2 Regulators & Flow
Calibration gases that are lighter than or the same weight as air (CO, O
2
, etc.) should be fl owed at
0.5 LPM. Gases heavier than air (NO
2
, etc.) should be fl owed between 0.5 and 1.0 LPM. Fixed fl ow
regulators provide more accuracy.
8.1.3 Adapters
The proper calibration adapter should be utilized to allow the gas to properly diff use around the
sensor. The calibration adapter plug for an LPT without a splash guard is part number
CET-7000-
CAP
. For an LPT with a splash guard, you will need to use the Cal Clip, part number
CET-SGC
.
