Calibration - EMS 5003 Operator's Manual

Calibration

Figure 24 Figure 25
NOTE: The hydrocarbon gas in the calibration cylinder is propane (LPG), 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 (Figure 25) 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. The PEF value (
Propane equivalence factor) can be used to calculate the Hexane gas value. You have
access to the bench PEF value in the SETUP Menu screen. You can also go into the fuel
selection screen and pick LPG for an accurate calibration gas value that the display calcu-
lates automatically. NOTE: EMS recommends allowing the analyzer to warm up for a
min. of 1 hour before calibrating. You may also need to calibrate more than once to
get the Nox sensor to calibrate more accurate, ecspeacially for BAR 97 HIGH gas.
If checking accuracy you will also see the Nox get more accurate as you allow the
analyzer to run, warming up all the sensors to a consistent temperature approx. 2-
3 hours.
After calibration you will see a Bad Nox sensor message, this is a False error we
can't seem to eliminate! Zero the analyzer on the Home screen to clear the error
message.
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