CODEL Energy Tech 401 Installation, Operation And Maintenance Manual page 57

4.8.1.9 Measurement Path
Length.
The current value entered for the path length will be displayed for 1 second then the display will default to zero. The
path length must be re-entered for the unit to calculate gas concentrations correctly. (The display below shows the
screen after 1 second, before the path length is reconfigured).
The path length entered must represent the length of the actual gas pass, NOT the flange-to-flange dimension
between the transmitter and receiver.
4.8.1.10 Alarm
Issue: A Revision: 1 Date: 24/07/19
The transmissivity of a sample of any gas depends both on the concentration and
on the path length through which the radiation is transmitted. Similarly, the
output of the CODEL gas monitor also depends upon the path length of the flue
gas through which the radiation is transmitted.
NOTE
See also Points to Consider.
Effectively, the CODEL analysers are sensitive to the product of concentration x
path length, and in order to obtain a true value of concentration of gas, it is
necessary to input the correct path length into the processor. This value is then
used to produce a final value of gas concentration.
NOTE
A contact output is available to warn of a high gas concentration. This contact
output may be triggered from any of the four averaging stacks. Select its source
with the ARROW key and enter it with the ENTER key.
Ref: 100606
Section 4
Commissioning
Page: 57