Teledyne Percent Oxygen Analyzer Applications Not at Atmospheric Pressure, Sensor Impedance

Operational Theory Model 9060L

THE PROBE/SENSOR MUST ALWAYS BE

CONNECTED TO EARTH.

Power to the heater is supplied directly from the main power source, and the temperature is initially controlled above 700°C (1300°F) after power up.

2.3 Applications Not at Atmospheric Pressure

For high and low pressure applications where the pressure at the point of measurement is significantly above or below atmospheric pressure, compensation must be applied. The Model 9060L does not incorporate a pressure sensor thus no compensation is performed. This factor must be considered when reading concentration from the display under high or low pressure monitoring conditions.

2.4 Sensor Impedance

The zirconia sensor impedance is a basic measurement of the reliability of the oxygen reading. A probe or sensor with a high impedance reading will eventually produce erroneous signals. The analyzer checks the zirconia sensor impedance every 5 minutes and if the impedance is above the maximum level for a specific temperature then the impedance alarm will be activated. Typical sensor impedance is 1 KΩ to 8 KΩ at 720°C (1320°F).

2.5 Electronics

2.5.1 General

The signal processing uses an Intel® micro-controller with on-board RAM and ROM to control all signal processing, input/output, and display functions for the analyzer. System power can be either 120 or 220 VAC depending on the position of an internal switch.

The power supply circuitry and temperature controller circuitry are on the Power Supply PCB, which is mounted vertically, just behind the rear panel of the control unit.

The signal processing electronics including the sensor amplifier, micro-controller, analog to digital, and digital to analog converters are

Teledyne Analytical Instruments 20