Model OT-2 System | Operational Theory 2 |
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2.3Electronics and Signal Processing
The OT-2 circuitry consists of three stages: an input stage, a temperature compensation/gain stage and an output stage.
The input stage consists of a current to voltage converter producing a voltage signal that is proportional to the oxygen concentration as detected by the sensor.
The temperature compensation stage contains circuitry that compensates for the temperature effects on the output current of the O2 cell. A thermistor mounted in the sensor assembly monitors the sensor temperature.
The output stage provides a 1-5 volt signal into a load >10K ohms corresponding to 0-100% of full scale of the selected range.
The transmitter circuitry operates with a power supply voltage range of 9-16 VDC. It is recommended that the output cable be no longer than 10 feet. A shielded cable should be used when- ever possible to minimize electrical noise pickup.
2.4Oxygen Cell Block Heater
The OT-2 system is equipped with an insulated and electrically heated cell block. The heater is switched on when the enclosure temperature dips below 1oC. The 3 watt heater is controlled by the electronic control unit.
Note: The cell block insulation must be in place for the heater system to be effective.
2.5EMI/RFI Protection
The OT-2 System is well shielded from EMI/RFI. The transmitter electronics are mounted within a grounded metallic enclosure, and the electronics is housed within the main system enclosure. For optimal transmitter performance, the main system enclosure should be well grounded.
Teledyne Analytical Instruments | 2-7 |