Teledyne API Model 200AH NOX Analyzer Instruction Manual, 06492, Rev. G2

9-19

9.1.5. Test Channel Analog Output

Many of the TEST functions have an analog voltage associated with them. As a diagnostic aid it

is possible to route the various test voltages out the 4th analog output port. Details on using the

test channel analog output are in the Troubleshooting Section.

Table 9-6: Test Channel Readings

TEST Channel Minimum* Maximum* Description
PMT
DETECTOR 0 mV 5000 mV PMT detector output from the preamp. This
signal has been amplified and filtered. Since the
instrument is switched and uses AutoZero,
normal values can vary from -100 to 5000 mV.
Wide variations in this signal are normal.
Values should be around 0 mV when sampling
zero air.
OZONE FLOW 0 cc/min 1000 cc/min This signal is the output from the ozone
flowmeter. Values around 1150 mV indicate
zero flow. Typical values for 80 cc/min ozone
flow are around 1800 mV. Voltage should be
steady, indicating stable flow.
SAMPLE
FLOW 0 cc/min 1000 cc/min The sample flow is calculated from the
upstream pressure as measured by the
SAMPLE PRESSURE transducer.
SAMPLE
PRESSURE 0" Hg-Abs 40"-Hg-Abs The sample pressure is measured by an absolute
pressure meter. The absolute pressure at sea
level is 29.92"-Hg. The exact reading will vary
a few tenths due to passing weather fronts and
daily temperature cycling. The reading will
decrease about 1"-Hg with each 1000 ft gain in
altitude. For example, the absolute pressure at
10,000-ft (3000 m) is about 20"-Hg-A. A
typical value near sea level would be about
4200 mV.
RCELL
PRESSURE 0" Hg-Abs 40"-Hg-Abs Like the SAMPLE PRESSURE the RCELL
pressure is an absolute pressure measurement.
With the sample pump off, it should read about
atmospheric pressure. With the pump
operating, a typical value is 1300 mV for about
5"-Hg-A reaction cell pressure.
(table continued)