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Back Pressure Regulator
Reaction Chamber
Pressure Regulator and
Software
Instrument Control
Thermo Fisher Scientific
Controls back pressure flow through the system.
The reaction chamber is where the sample reacts with ozone and produces
excited NO
The reaction chamber is heated and controlled to approximately 50 °C to
ensure optimum instrument stability.
Regulates and measures gas flow through the system.
Gauge
The processor software tasks are organized into four areas:
•
Instrument Control
•
Monitoring Signals
•
Measurement Calculations
•
Output Communication
Low-level embedded processors are used to control the various functions on
the boards, such as analog and digital I/O and heater control. These
processors are controlled over a serial interface with a single high-level
processor that also controls the front-panel user interface. The low-level
processors all run a common piece of firmware that is bundled with the
high-level firmware and loaded on power-up if a different version is
detected.
Each board has a specific address that is used to identify to the firmware
what functions are supported on that board. This address is also used for the
communications between the low-level processors and the high-level
processor.
Every tenth of a second the frequency counters, analog I/O, and digital I/O
are read and written to by the low-level processor. The counters are
accumulated over the past second and the analog inputs are averaged over
that second. The high-level processor polls the low-level processors once per
second to exchange the measurement and control data.
that gives off a photon of energy when it decays.
2
System Description
Software
Model 146i Instruction Manual
8-7
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Troubleshooting
