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Heatpipe Furnace Models 17702W, 17702P, 17702S (13
–
07/20)
PROCESS TO APPLY A USER LINEARIZATION TO THE HEATPIPE FURNACE
From time to time the control sensors inside the furnace will need to be adjusted as the sensor drifts with
time and use at high temperature. The controller has the capability to compensate for these errors using
an eight point correction curve. This will need to be regularly checked for errors and can easily be
corrected within the controller using the following procedure.
The image below illustrates a simplified graphical view of the process.
Isotech standard offset values are set at the following temperatures:
This is listed as Channel 1 on the controller
17702S
17702P
17702W
450°C
420°C
125°C
660°C
660°C
156°C
960°C
960°C
230°C
1080°C
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Non populated points are unused as standard.
Please follow the procedure below to linearise the controller display value:
1.
For the heatpipe furnace, set the furnace up as it will be used with a fixed point cell using either a
cell or a simulation of the cell using a thermally efficient metal block suitable for use over the
temperature range (Inconel 600 would be ideal)
2.
Place a reference thermometer inside the cell
3.
Set the furnace to the lowest useable temperature (recommendation would be to use the
temperatures listed above)
4.
Allow the system the thermally stabilise
5.
Press the PAGE button to enter the SUPERVISOR menu
6.
Scroll to the CHANNELS tab and enter with the SCROLL button
7.
Select CHANNEL 1
8.
Scroll to the ISOTECH tab and enter with the SCROLL button
9.
Scroll to CAL STATUS and enter with the SCROLL button
10.
Scroll to POINT 1 and enter the value from the reference thermometer
The controller is now ready to accept a value. Ensure the equipment is thermally stable, you will now need
to use the temperature value displayed by the reference thermometer.
