Teledyne 3000 Ultra Trace - PPB oxygen analyzer - Manual (Page 22)

2-10
2 Operational Theory Model Ultra Trace 3000
Teledyne Analytical Instruments
In the presence of oxygen the cell generates a current. A current to
voltage amplifier converts this current to a voltage, which is further amplified
in the second stage amplifier.
The output from the second stage amplifier is sent to an 18 bit analog
to digital converter controlled by the microprocessor.
The digital concentration signal along with input from the control panel
is processed by the microprocessor, and appropriate control signals are
directed to the display, alarms and communications port. The same digital
information is also sent to a 12 bit digital to analog converter that produces
the 4-20 mA dc and the 0-1 V dc analog concentration signal outputs, and
the analog range ID outputs.
Signals from the power supply are also monitored, and through the
microprocessor, the system failure alarm is activated if a malfunction is
detected.