Teledyne 9110TH - Nitrogen Oxides Analyzer - Manual (Page 298)

Model 9110TH NOx Analyzer Principles of Operation
Teledyne Analytical Instruments 278
Figure 8-14: Oxygen Sensor - Principle of Operation
8.4.2. OPERATION WITHIN THE 9110TH/M ANALYZER
The oxygen sensor option is transparently integrated into the core analyzer operation.
All functions can be viewed or accessed through the front panel, just like the functions
for NO
X
.
 The O2 concentration is displayed in the upper right-hand corner,
alternating with NOX, NO and NO2 concentrations.
 Test functions for O2 slope and offset are viewable from the front panel
along with the analyzer’s other test functions.
 O2 sensor calibration is performed via the front panel CAL function and is
performed in a nearly identical manner as the standard NOX/NO
calibration. See Section 5 for more details.
 Stability of the O
2
sensor can be viewed (see 3.3.2.1)
The O
2
concentration range is 0-100% (user selectable) with 0.1% precision and
accuracy and is available to be output via one of the instrument’s four user selectable
analog outputs (see Section 6.13.4).
The temperature of the O
2
sensor is maintained at a constant 50° C by means of a PID
loop and can be viewed on the front panel as test function O2 TEMP.
The O
2
sensor assembly itself does not have any serviceable parts and is enclosed in an
insulated canister.
8.4.3. PNEUMATIC OPERATION OF THE O
2
SENSOR
Pneumatically, the O
2
sensor is connected after the particulate filter and draws a flow of
about 80 cm³/min in addition to the normal sample flow rate (See Table 10.-3 for
nominal sample inlet gas flow rates) and is separately controlled with its own critical
flow orifice located inside the vacuum manifold.