14
3.3 Temperature Offset Calibration
The control probe may need to be calibrated once the unit has passed the stabilization period. A good
laboratory practice would require at least annual calibration check.
Calibrating the Control Probe
Place a calibrated temperature recording instrument next to the PT100 sensor located inside the sensor cover
at the bottom right corner of the cabinet. Allow the freezer to stabilize for at least 2 hours if the unit has been
in service or at least 12 hours if the freezer is being started up for the first time. Compare the calibrated
temperature reading to the freezer display temperature. The offset value is determined by the difference
between the two readings.
Warning:
It is imperative that only properly calibrated reference instruments should be used for calibration
Step
Action
1
Access MENU by pressing MENU key.
2
Move the ‘>’ sign by using
▲
or
▼
key to point to CALIBRATION.
3
Press SET key to confirm the selection.
4
Select which temperature sensor you need to calibrate by using the same method as the above.
5
To do calibration, select CALIBRATE.
5.1
Key in the measured value by using
▲
or
▼
key. Program will ask you to key in.
5.2
Confirm the keyed in value by pressing SET. You will get “CALIBRATION OFFSET STORED”
confirmation on the LCD from the program.
6
Confirm the keyed in value by pressing SET. You will get “CALIBRATION OFFSET STORED”
confirmation on the LCD from the program.
Temperature Stabilization Periods
-
Startup –
Allow 12 hours for the temperature in the cabinet to stabilize before proceeding with
calibration
-
Already Operating –
Allow at least 2 hours after the display reaches temperature set point in order
for the temperature to stabilize before proceeding with calibration.
3.4 Temperature Settings
The freezer is shipped from the factory with temperature set point of -80
o
C. To change temperature settings,
you need to access SETTINGS menu. All menu options under SETTINGS menu are used to configure the settings
for temperature chamber only.
3.4.1 SET TEMP
Your Scancool Classic ULT Freezer temperature set point ranges from -40
o
C to -86
o
C. The default factory
temperature set point is -80
o
C.
Note:
If the set point is changed, the high and low alarm limit will change automatically. For example: initial temperature
set point: -80°C; low alarm limit: -90°C; high alarm limit: -70°C. If the temperature set point is subsequently changed to -
83°C, then the high and low alarm limit will adjust automatically to -73°C and -93°C.
3.4.2 SET HIGH ALARM
Your Scancool Classic ULT Freezer high alarm temperature set point ranges from SET POINT+ 5
o
C to SET POINT
+10
o
C. The default value is SET TEMP +10
o
C.
3.4.3 SET LOW ALARM
Your Scancool Classic ULT Freezer high alarm temperature set point ranges from SET POINT-10
o
C to SET POINT
-5
o
C. The default value is SET POINT -10
o
C.
