Emerson Process Management 760004-A - Manual (Page 21)

Instruction Manual
760004-A
February 2002
Rosemount Analytical Inc. A Division of Emerson Process Management Description and Specifications 2-1
Model NGA 2000 HFID
SECTION 2
INSTALLATION
2-1 UNPACKING
If the HFID Analyzer Module is received as a
separate unit, carefully examine the shipping
carton and contents for signs of damage. Im-
mediately notify the shipping carrier if the carton
or contents is damaged. Retain the carton and
packing material until all components associ-
ated with the Analyzer Module are operational.
2-2 ASSEMBLY
If the Analyzer Module requires assembly with
other components, do so at this time.
Connect the network cable to either the NET-
WORK 1 or NETWORK 2 connection on the
Analyzer Module. Connect the power cable to
the Analyzer Module front panel and an electri-
cal +24VDC power supply.
2-3 LOCATION
Install the Analyzer Module in a clean,
weather-proofed, non-hazardous, vibration-free
location free from extreme temperature varia-
tions. For best results, install the Analyzer Mod-
ule near the sample stream to minimize sample
transport time.
WARNING
INSTALLATION RESTRICTIONS
For safety, the Analyzer Module should be
installed in a non-confined, ventilated space.
Do not block any of the rear panel outlets as
they are part of the safety system.
Operating ambient temperature is 15 °C to
35 °C, limited to temperature changes of less
than 10 °C/hr. Acceptable dew point range is
less than 95% relative humidity, but not in ex-
cess of 45
°C wet bulb temperature.
The cylinders of fuel, air, and calibration
gas(es) and the source of purge and regu-
lated air should be located in an area of
relatively constant ambient temperature.
2-4 GASES
a. Overview
During normal operation, the Analyzer
Module requires fuel and air to maintain the
burner flame as well as suitable standard
gases for calibration and instrument air for
purge requirements. In addition, instrument
air for regulated air in is required to control
the sample pressure at the sample capillary.
Criteria for selection of these gases follow in
Section 2-4c.
After initial startup or after startup following
a prolonged shutdown, the analyzer may
display baseline drift for a considerable pe-
riod of time, particularly on the most sensi-
tive range. Commonly, the drift is caused by
small amounts of hydrocarbons in the inner
walls of the tubing in both the internal flow
system and the external gas supply system.
Drift results from any factor influencing the
equilibrium of these absorbed hydrocar-
bons, such as temperature or pressure.
Note that this type of drift occurs only when
the flame is burning. If drift occurs when the
flame is extinguished, the electronic circuitry
is at fault. To minimize drift, use clean fuel
and air, keep the analyzer clean, and locate
the gas cylinders in an area of relatively
constant ambient temperature.
The cylinders supplying all gases each
should be equipped with a clean, hydrocar-
bon-free, two-stage regulator and a shutoff
valve.
All new external gas tubing (except for
PURGE IN/OUT and SAMPLE BYPASS) is
strongly recommended, preferably pre-
cleaned, stainless steel, gas chromato-