Thermo Scientific 42i Instruction Manual page 248

Optional Equipment
Internal Permeation Span Source
Permeation Tube Oven
Calibration
Setting Perm Oven
Temperature
9-6 Model 42i Instruction Manual
17. Remove resistor from POJ3 and re-attach the permeation oven.
18. Perform a thermistor calibration using the
Calibration" procedure that follows.
There are two general approaches that can be used to calibrate the
permeation tube oven. The first is to calibrate the temperature indicator
very accurately (to better than 0.02 °C) and to use a permeation tube whose
weight loss has been previously determined at that temperature.
Note An error of approximately 0.1 °C corresponds to an error of 1% in
release rate. ▲
The second approach is to note that the thermistors used to measure
temperature are interchangeable to better than ±0.2 °C. Thus a 1% resistor
of the proper value (4.369 K
measurement interface board. The release rate for the permeation tube is
then determined by weight loss in the actual oven being used.
You can use either of the two calibration methods presented here. One
method involves performing the "Setting Perm Oven Temperature"
procedure and then continuing with the "Setting Temperature with Water
Bath" procedure.
Alternatively, you can perform the "Setting Perm Oven Temperature"
procedure and then continue with the "Setting Temperature with Known
Resistance" procedure.
In either case, use the following procedure for setting the perm oven
temperature.
1. Unplug POJ3 from the measurement interface board. Place a 4.369 K
resistor across pins 3 and 4 on the board.
2. In the Main Menu, choose Service > Perm Oven Settings > Cal Oven
Thermistor.
"Permeation Tube Oven
Ω
for 45 °C) can be used to set the span on the
Thermo Fisher Scientific