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System Description
Electronics
Pressure Sensor Assembly
Ozonator Lamp Power Supply
8-10
Model 146i Instruction Manual
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Data communication with the motherboard
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24V and 120VAC power supply inputs
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Fan and solenoid outputs
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120VAC outputs for the photometer pump
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Two mass flow controllers
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Pressure sensor inputs
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Detector board inputs
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Internal temperature thermistor
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Photometer temperature thermistor
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Ozonator lamp power supply
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Photometer lamp power supply
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Permeation oven temperature thermistor and heater control
The pressure sensor assembly consists of a board containing an
instrumentation amplifier and a pressure transducer with a gas input fitting.
The pressure transducer output is produced by measuring the pressure
difference between the sample gas pressure and ambient air pressure.
The ozonator lamp power supply board includes the circuits that generate
high voltage AC to control the lamp heater. A transformer outputting high
voltage at approximately 15 kHz drives the lamp. A resistor in series with
the output limits the lamp current. The voltage output is adjustable under
software control for lamp intensity control. The ozonator lamp can be
switched on and off under software control.
The lamp is heated to a specific temperature to ensure reliable operation.
The oscillator circuit that drives the high voltage output is inhibited until
this operating temperature is reached. A power transistor is used to heat the
lamp housing. Thermistors sense the housing temperature for heater control
and for status information.
Thermo Fisher Scientific
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Troubleshooting
