Cryo-con Model 24C
Basic Setup and Operation
CalGen Initial Setup
Generation of a calibration curve using CalGen requires the measurement of various
temperature points. Therefore, an input channel must be configured with the correct
sensor before the CalGen process can start.
To initiate the curve generation, select the CalGen field on the Input Channel Setup
menu. This takes the screen to a sub-menu for the specific sensor type.
i
Note:
Before CalGen can be initiated, there must be a valid
temperature reading on the selected input channel. If this is not the
case, selecting the CalGen
field will cause the display of an error
message.
When the input channel has a valid reading, CalGen determines if the sensor is a
diode or Platinum sensor. The calibration curve of the selected input sensor is used
as the input to the curve generation process.
Using CalGen With Diode Sensors
Options for generating diode calibration curves are:
1. One point near 300K. The portion of a diode Sensor curve above 30K is fit to
a user-specified point near 300K. This is a two-point fit where the 30K point is
taken from the existing calibration curve. The portion of the curve below 30K
is unaffected.
2. Two points: 300K and 77K. Here, two user-specified points are taken to fit the
diode curve region above 30K. The entire curve is offset to match the 77K
point, then, the >30K region is fit to the two points.
3. Three points: 300K, 77K and 4.2K. Two points above 30K are fit as in the
selection above. Then, a third point is used to fit a single point in the high-
sensitivity region below 20K.
4. One point near 4.2K. This is a two-point fit where the 20K point is taken from
the existing calibration curve. The portion of the curve above 20K is
unaffected.
For a diode sensor, a sub-menu is displayed that allows the user to select the number
of points desired for the CalGen fit.
First CalGen
Menu, Diode Sensor
1pt CalGen @300K
Pressing the
Enter
key will select curve generation with a
single point near 300K.
2pt CalGen
Pressing the
Enter
key will select curve generation at two
points where both points must be > 50K.
3pt CalGen
Pressing the
Enter
key will select curve generation three
points: Two above 50K and one near 4.2K.
1pt CalGen @4.2K
Pressing the
Enter
key will select curve generation with a
single point near 4.2K.
Table 32: First CalGen Menu, Diode Sensor
From this screen, select the desired number of points. For example, select ‘2 point’.
This will take the display to the two-point curve generator screen shown here.
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