Maintenance
BDS 3960
Teledyne Analytical Instruments
48
3. After the sensor has been purged for at least two weeks and the
baseline is stable, monitor the oxygen reading and ambient
temperature over a minimum period of 24 hours.
Take the maximum and minimum oxygen readings, and the
maximum and minimum temperature readings.
4. Calculate the coefficient using the relation:
Coefficient = (O
2
max
- O
2
min
) ÷ (Temp
max
- Temp
min
)
For example:
In a 24 hour run:
O
2
max
= 3.55 ppb
O
2
min
= 1.75 ppb
Temp
max
= 24.5 degrees C.
Temp
min
= 22.1 degrees C.
Coefficient = (3.55-1.75)ppb ÷ (24.5-22.1) °C = 0.75 ppb/°C.
This value is currently set to zero, since the sensor is
temperature controlled and should be left at zero unless qualified
personnel give instructions to change it.
4.3.2.4 S
ET
D
EFAULTS
The
Set Defaults
button will reset all parameters in the software,
such as calibration, alarm and range settings, Filter, Gas Factor,
temperature coefficient, etc. to their factory default values. Some of the
default values are listed below:
Table 4-2: Parameter Default Values
Parameter
Default Value
Zero Offset
0
Span Gas
8.00 PPM
SpanFactor
24.42 (Default span factor =
100000 ppb/ 4095 ADC counts)
