Instruction manual
7 - 3
NGA 2000 MLT Hardware
MEASUREMENT/CALIBRATION//SWITCHING OFF
Emerson Process Management GmbH & Co. OHG
Instruction Manual
90002929
07/2005
CALIBRATION
7.2.1 Test Gases
7.2.1.1 Zero Gas
For zeroing, the analyzer has to be purged with nitrogen (N
2
) or adequate zero gas [e. g. synth. air
or conditionned air (but not for O
2
- measurement)]
.
7.2.1.2 Span Gas
The calibration of all another analyzers should be done with pure span gases in order to prevent
interferences between the gases (e. g., CO
2
and CO) measured by the analyzer, using test gas
mixtures.
The concentration range of the span gas has to be in a range of 80 - 100 % (70 - 110 %) of the
full - scale range of the respective measuring channel. For lower span gas concentrations the
measuring accuracy could be lower for sample gas concentrations, which are higher than the span
gas concentration! For test gas concentration see certification of the test gas bottles.
Spanning for oxygen measurement can be done using conditionned ambient air as span gas, if
the oxygen concentration is known and constant.
To calibrate the MLT 1 ULCO internal H
2
O channel (0-3 Vol.-%, used for cross compensation), use
water vapor saturated N
2
according to saturation characteristic (Item 22.) as span gas. Purge N
2
through a gas-blubber bottle, filled with distilled water and in a little bit higher ambient temperature
as necessary Connect a second vessel into a kyrostat (to hold ambient temperature constant) in
series to get defined dew point.
Take care of the safety instructions applicable for the gases (sample
gases and test gases) and for the gas bottles containing these gases!
Max. permissible gas pressure: 1,500 hPa, except instruments for gas purity
measurement (see chapter 5.4.3.1), with integrated valve blocks (see page 5-8) and/or
paramagnetic Oxygen sensor (see table page 20-4)!
An constant input pressure (± 70 hPa or ±1 psig) between 1,500 to 3,000 hPa (20 to 43
psig) is necessary for sample gas as well as for zero gas and span gas because of
internal pressure regulator (different input pressures look at order confirmation).
All calibration gases need to be kept to the same temperature as sample gas!
The calibration of MLT 1 ULCO must be done using pure test gases.