Teledyne GFC-7000T - Trace CO2 Analyzer - manual - Manual (Page 77)

FAQ Model GFC7000TA Carbon Dioxide Analyzer
Teledyne Analytical Instruments 59
Figure 5-5: Oxygen Sensor - Principle of Operation
5.6.1.2. Operation within the GFC 7000TA 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 CO
2
 The O
2
concentration is displayed in the upper right-hand corner, alternating with CO
2
concentration.
 Test functions for O
2
slope and offset are viewable from the front panel along with the analyzer’s
other test functions.
 O
2
sensor calibration is performed via the front panel CAL function and is performed in a nearly
identical manner as the standard CO
2
calibration. See Section 3.3.1 for more details.
 Stability of the O
2
sensor can be viewed via the front panel (see Section 3.3.2.1).
 A signal representing the currently measured O
2
concentration is available.
The O
2
concentration range is 0-100% (user selectable) with 0.1% precision and accuracy and is
available to be output via the instrument’s analog output channel A3 (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.
5.6.1.3. Pneumatic Operation of the O
2
Sensor
 Pneumatically, the O
2
sensor is connected to the bypass manifold and draws a flow of about 120
cm³/min in addition to the normal sample flow rate and is separately controlled with its own critical
flow orifice. Figure 5-8 shows the internal pneumatics of the GFC 7000TA with the O2 Sensor
installed.