Teledyne API Model 200AH NO
X
Analyzer Instruction Manual, 06492, Rev. G2
4-8
Table 4-2: Front Panel Status LED's
LED State Meaning
Green Off
On Monitoring
Blinking
NOT monitoring, DAS disabled
Monitoring normally, taking DAS data
Monitoring, DAS in HOLDOFF mode
(1)
Yellow Off
On
Blinking
AutoCal disabled
AutoCal enabled
Calibrating
Red Off
Blinking
No warnings exist
Warnings exist
(1)
This occurs during Calibration, DAS holdoff, after power-up and in Diagnostic mode.
4.2.6.3. Power Switch
The power switch has two functions. The rocker switch controls overall power to the instrument,
in addition it includes a circuit breaker. If attempts to power up the M200AH result in a circuit
breaker trip, the switch automatically returns to the OFF position, and the instrument will not
power up.
4.2.7. Power Supply Module
The Power supply module supplies AC and DC power to the rest of the instrument. It consists of
a 4 output linear DC power supply and a 15 volt switching supply. In addition, it contains the
switching circuitry to drive the DC operated valves and several switched AC loads to operate the
Rx cell heater, converter heaters and the ozone generator. The only voltages not generated in the
PSM are the high voltage DC required by the PMT which is generated inside the sensor module
and the high voltage AC used by the ozone generator.
4.2.8. Pump, Valves, Pneumatic System
A standard M200AH comes with 2 valves, the NO/NO
X
valve and the AutoZero valve, see
Figure 4-2. Depending on the selected operating mode, the NO/NO
X
valve:
1. NO only mode - routes sample gas continuously into the reaction cell.
2. NO
X
only mode - routes sample gas continuously through the converter, then into the
reaction cell.
3. NO/NO
X
switching mode - switches gas alternately around, then through the converter to
measure NO, NO
X
, and by calculation NO
2
.
The AutoZero valve provides a continuous zero reference. Periodically, the valve switches to
turn off sample gas to the reaction cell. The ozone continues to flow. The zero reading is
averaged and used to compensate subsequent readings for PMT zero offset.
