Teledyne API Model 200AU NOX Analyzer Instruction Manual, 02293, Rev. F
5-12
DC Power Supply (DCPS)
The DCPS voltage is a composite of the 5 and ± 15 VDC voltages in the Power Supply Module.
This is meant to be a quick indicator to show if the PSM is working correctly. The nominal value
is 2500 mV ± 200 mV.
Reaction Cell Temperature
This is a measurement of the temperature of the reaction cell. It is controlled by the computer to
40 ± 1° C. Temperatures outside this range will cause the M200AU output to drift.
Box Temperature
This TEST function measures the temperature inside the chassis of the M200AU. The
temperature sensor is located on the Status/Temp Board. Typically it runs 2 to 10° C higher than
the ambient temperature.
PMT Temperature
The temperature of the PMT is closely controlled by a dedicated proportional temperature
controller. The nominal set-point is -5 ± 1° C. Readings outside this range will cause instrument
drift due to gain changes in the PMT detector.
Block Temperature
The temperature of the sample flow and ozone flow control orifice blocks. The nominal set-point
is 40 ± 1° C. Readings outside this range will cause instrument drift.
Moly Temperature
The moly temperature is controlled by the computer. The nominal set-point is 315 ± 5° C. The
temperature sensor inside the moly is a type-J thermocouple. The thermocouple amplifier is
located on the STATUS/TEMP board. If the thermocouple breaks, the reading will go to 500° C
and remove power from the heater.
Reaction Cell Pressure
The pressure in the reaction cell is measured by a solid state pressure sensor, which measures
absolute pressure. This pressure will vary depending on several things.
1. The type of pump attached to the analyzer.
2. Variations in local weather will cause a ± 0.3in-Hg change in pressure.
3. The altitude of the analyzer will cause the cell pressure to change.
Nominal values are 1 to 4 in-Hg-A. typical reading is about 3.5 in-Hg-A.