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TAI Model 6400A SO
If the SO
of 1000 ± 100 ppb, then the lamp ratio may need to be updated.
See Section 9.1.6, step 2 of PMT Calibration procedure.
9.1.3.3 Optic Test
Optic test turns on a small LED inside the PMT housing which simulates the signal from the
reaction cell. OT tests the entire signal detection subsystem. By observing the level, noise and
drift of this test, correct operation of many sections of the analyzer can be verified.
The implementation of OT involves several changes to the instrument operating conditions. The
6400A does the following when switching to optic test:
1. Save the current instrument setup as to autorange, dual range, current range. D/A analog
output is set at 2000 ppb range and auto-ranging is disabled.
2. Allow to sample zero gas.
3. Select SETUP-MORE-DIAG, scroll to select the optic test and push ENTR button.
4. The PMT reading in TEST functions should be 2000 ± 1000mV.
If the HVPS or the span gain adjust on the preamp card has been changed without doing a
FACTORY CALIBRATE the reading in step 4 may be different than 2000 mV, since the overall
calibration affects OPTIC TEST. Also if the SO
range of 1000 ± 500 ppb, then the lamp ratio may need to be updated. See Section 9.1.6 for factory
calibration procedure.
9.1.3.4 Analog Out Step Test
The Step Test is used to test the functioning of the 4 DAC outputs on the V/F board. The test
consists of stepping each analog output 0-20-40-60-80-100% of the output. If the analog outputs are
set for 0-5V full scale the outputs would step 0-1-2-3-4-5VDC. The stepping can be halted at any
value by pressing the key under the percentage on the front panel. When the test is halted, square
brackets are placed around the percentage value in the display. Pressing the key again resumes the
test. This test is useful for testing the accuracy/linearity of the analog outputs.
Analyzer Operator Manual, 02164, Rev. G
2
NOTE
concentration display is not within the nominal range
2
concentration display is not within the nominal
2
9-17
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Troubleshooting
