Table of Contents
Advertisement
The gas analyzer should be checked periodically for accuracy. EMS recommends the
analyzer be re-calibrated every 6 months minimum for a 5 gas unit The analyzer can be cali-
brated in the field. In order to perform the calibration procedure you will need a bottle of cali-
bration gas and a calibration kit assembly (Figure 14). The calibration assembly can be pur-
chased from EMS or your local distributor. The recommended calibration gas is Bar 97 Low
and can be purchased from EMS or a local specialty gas supplier.
Calibration Procedure:
1. To begin the calibration procedure depress the "Z" and "C" buttons together. Note: If
the "C" button is pushed too late the analyzer will begin the zeroing procedure. If
this occurs, wait until the zero procedure is complete and try again. The analyzer
display will go blank if the buttons are depressed properly. Release the buttons and the
display will show the stored calibration gas values. Compare these numbers to the
calibration gas bottle. If the numbers do not match, they can be changed using the "Z"
and "C" buttons. The "C" button will change the number that is flashing. Once the flash-
ing number is adjusted to the correct value, the "Z" button is be used to cycle to the
next digit. This process is continued until all the calibration gas values are correct.
Note: The NOx gas concentration value is displayed in the 02 window.
2. Once the calibration gas values have been verified or adjusted, the calibration proce-
dure can continue. Depress the "Z" and "C" buttons together. The analyzer display will
go blank. Release the buttons and the analyzer will begin the calibration sample mode.
The display will show current sample values and then display dashes.
3. Connect the hose from the regulator assembly to the sample hose inlet. Open the
valve on the gas bottle. (Note: Do not adjust the regulator, this was preset to the
appropriate flow value.) Once the calibration gas values stabilize, depress the "C"
button. The analyzer will capture the gas concentrations and perform the final calibra-
tion procedure. The calibration process is now complete.
4. If the calibration procedure was unsuccessful, error numbers will flash along with the
sample numbers. If this occurs, perform the calibration procedure again. If the problem
continues, contact EMS or your local distributor. NOTE:
calibration cylinder is propane, and the gas analyzer generally measures hexane. This
is problematical, as hexane is a molecule that is about twice as large as propane. This
means that the typical HC reading on the gas analyzer (hexane) should be about ½ the
propane value on the calibration cylinder tag. That is, if the tag states that the cylinder
contains 1200 ppm propane, then an analyzer measuring HC as hexane will report HC
at about 600 ppm.
Calibration
Figure 14
11
The hydrocarbon gas in the
Advertisement
Table of Contents
