Specifications

Trace Oxygen Analyzer Module
Rosemount Analytical NGA 2000
748420-A
August 1999
7
I
NSTALLATION
2
Sample
The sample must be clean and dry before entering the Analyzer Module. Sample should be
filtered for particulates down to two microns, and should have a dew point at least 5
°
C (13
°
F) below the coldest expected ambient temperature.
Pressure
Constant between 13.8 and 69 hPa - gauge (0.2 and 1.0 psig) sample inlet pressure is
recommended. If a needle valve is used upstream of the Analyzer Module to control flow,
the inlet pressure to the needle valve should not exceed 345 hPa (5 psig). A constant
sample flow rate between 1.0 to 3.0 SCFH (0.5 to 1.5 l/min) is recommended for best
results. The Analyzer Module must vent to atmosphere to avoid back pressure influences
on the oxygen reading.
2.4.2 C
ONNECTIONS
(See Figure 2-3. ) Connect inlet and outlet lines for sample to appropriately labeled fittings
on the rear panel. SAMPLE IN and SAMPLE OUT are 1/4-inch ferrule-type compression
fittings. Zero and span gases should be introduced at the SAMPLE IN fitting at normal
sample inlet flow rate.
Metallic tubing is recommended for the sample line. The use of plastic, Teflon, or other non-
metallic tubing can result in ambient oxygen permeation through the tubing causing higher
than expected reading. Exhaust tubing should be 1/4 inch (6.3 mm) or larger, and can be
metallic or non-metallic.
F
IGURE
2-1. A
NALYZER
M
ODULE
I
NTERCONNECTION WITH
I
NSTRUMENT
P
LATFORM
ANALYZER MODULE
CONNECTIONS
BACKPLANE
CONNECTIONS
Fuse
Power
Network 2
Network 1
Power Indicator Light
Power
Network
Controller Board
Connector
Backplane