Teledyne operating instructions Operational Theory Model 3300TB

2 Operational Theory Model 3300TB

In the presence of oxygen the cell generates a current. The sensor has an internal thermistor compensation network.

The output of the sensor is converted to voltage millivolt range. This output is fed to a voltage amplifier. The internal thermistor network provides tempera- ture compensation of the sensor output. The resistance of the network changes with temperature, compensating for the changes of the microfuel cell output to temperature.

The output from the temperature compensation amplifier is sent to an analog to digital converter (ADC), and the resulting digital concentration signal is sent to the microcontroller.

The digital concentration signal along with input from the front panel buttons (KEYBOARD) is processed by the microcontroller, and appropriate output signals are directed to the display and alarm relays. The same digital information is also sent to a 12-bit digital to analog converter (DAC) that produces the 0-10

Vdc analog concentration signal and the 0-10 V dc analog range ID output. A voltage current converter (E–I CONV) produces the 4-20 mA dc analog concentrationsignal.

2-6 Teledyne Analytical Instruments