Teledyne 6200A Manual page 147

TAI Model 6200A SO
Table 9-1: Test Functions (Continued)
Test Function Factory Set-Up
PRES Check value in
Final Test
Values
Table 2-1
SAMP FL 700 ±10%
(table continued)
Analyzer Operator Manual, 02164, Rev. G
2
Comment
Reaction cell pressure is measured to monitor sample pressure
and to compensate any sample pressure variation. Reaction cell
pressure is typically 2 Hg-In lower than the ambient pressure
due to the internal pressure drop.
Faults are caused due to:
Pneumatic leak
Faulty pressure sensor
Sample line flow restriction
see Section 9.3.6 Pres/Flow Sensor.
This is the instrument flow. It is measured by the solid state
flow meter. Incorrect flow can be caused by the plugged orifice,
pneumatic leak, or the flow meter itself.
- A rTAId method of determining if the orifice is plugged is to
disconnect the sample tube from the reaction cell, then briefly
put your finger over the fittings on the cell. You should feel the
vacuum build up.
- Another reliable method is to attach a rotameter or soap
bubble flowmeter to the fittings to measure the flows.
Flow rate will change ± a few cc/min due to changes in ambient
air pressure such as cycling of air conditioning, or passing
weather fronts. Changing altitude changes the ambient air
pressure and therefore the sample flowrate. Flow variation have
a negligible effect on the analyzer reading. See Section 9.2.2
Flow Check.
9-4