Oxygen Analyzer | Maintenance | |
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*Output normalized by calibrating with a span gas in N2.
The values in Table
The working range of adjustment is 0.25 to 2.50. This factor will divide the output. For example if the factor is set to 2.00, the output of the sensor, when read by the PPC application will be divided by two.
Special consideration on the working range: Changing the gas correction factor has an effect on the maximum working range of the analyzer, e.g.: if a gas factor of 2.00 is selected the maximum working range of the analyzer is 50 ppm. Any reading above this, may saturate the amplifier.
4.3.2.3TEMPERATURE COEFFICIENT
The output of the sensor is affected by temperature. There are two types of temperature compensation on the BDS 3960. One is the compensation to high levels of oxygen, more than 100 ppb. This effect is transparent to the user and is handled by the software application on the PPC. It requires no input from the user. The second compensation involves the baseline drift due to temperature. This value is generally set at the factory but can be modified or adjusted by the user. Since the sensor is temperature controlled, the default is zero. The following discussion is just information on its possibilities.
The baseline drift temperature coefficient is a number with units of ppb/degree centigrade and must be matched to the sensor’s characteristic drift over temperature. This coefficient ranges from 0.50 to 1.75 ppb/°C.
Note: The coefficient is different from sensor to sensor. If the sensor is replaced, a new coefficient must be entered. TAI can supply this coefficient or it may be determined by the user.
The coefficient can be adjusted between 0.00 and 5.00 using the Up and Down buttons on the instrument. To estimate it in the field:
1.Set the coefficient to zero.
2.Run the analyzer on “Zero” calibration gas for two weeks or until a baseline stability is reached, i.e. the oxygen reading does not fluctuate.
Teledyne Analytical Instruments | 47 |
