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Teledyne API Model 200AU NO
X
Analyzer Instruction Manual, 02293, Rev. F
9-17
4. To turn off ET press EXIT
If ET is a steady 2000
±
500 mV, that means the Power Supply Module, Preamp buffer
amplifier, V/F, CPU, and display are all working properly.
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
M200AU does the following when switching to optic test:
1. Saves the current instrument setup as to autorange, indep range, current range and places
the instrument into the 2000 ppb range.
2. Turns off power to the ozone generator to assure there is no interfering light from the
reaction cell.
3. Disables the PRE-REACTOR circuit.
4. Turns on the OT LED.
Procedure:
1. Scroll the TEST function to PMT.
2. Press SETUP-MORE-DIAG, then scroll to OPTIC TEST by pressing the NEXT button.
When OT appears, press ENTR to turn it on.
3. The value in PMT should come up to 2000 mV
±
1000 mV in less than 15 sec.
4. To turn off OT press EXIT.
If the PMT reading observed in step three comes up to the stated value, the instrument is capable
of responding to the light generated by the chemiluminescent reaction. If the instrument passes
OT, but there is absolutely no response to span gas, the most common cause is that the ozone
generator is either broken or is turned off. A second common cause, is that what is thought to be
span gas is actually zero gas.
If the HVPS or the span gain adjust on the preamp card has been changed without doing a
FACTORY CALIBRATE the reading in step 3 may be different than 2000 mV, since the overall
calibration affects OPTIC TEST. See Section 9.1.6 for factory calibration procedure.