Thermo Scientific 7451 Operating And Maintenance Manual page 37

Section 3
Configuration/Calibration
Menu Entry
Definitions (cont.)
3-2 Controlled Rate Freezer
B. Chart Recorder:
Selects the chart recorder operating parameters and checks
calibration. Exit this menu by using the Back key.
a. Select Chart Recorder Output:
Select chamber only, sample only, chamber/sample scan (2 sec.
chamber, 10 sec. sample), or no chart recorder function (Off ).
The default setting is Off.
b. Calibration/Linearity Verification:
Verify chart recorder calibration and linearity by setting the chart
recorder function over a range of -180°C (0VDC) to +50°C
(approximately 10VDC) in 10° steps.
Note The chart recorder function matches the non-linear scale on the chart
paper (see Section 7 - Parts List).
Customer-Provided Flatbed Recorder Calibration Procedure
1. Press the power switch on the flatbed recorder and allow the system to
warm-up for 20 minutes.
2. Uncap and lower the pen to the graph paper.
3. From the freezer Configure-calibrate menu, select Chart Recorder. Turn
the chart recorder on to Scan mode and press the Enter key.
4. Set the temperature to 0°C (zero). IMPORTANT: If the temperature is
already set to 0°C, move it up or down 10°C, then back to 0°C. The
recorder pen should move to 0°C. If it does not, adjust it using the zero
knob on the recorder until the pen reaches 0°C.
5. Set the temperature to -180°C to simulate the low end of the scale. The
recorder pen should move to -180°C. If it is out of calibration, adjust it
using the small screw (accessible through the hole adjacent to the zero
knob) until the pen reaches -180°C.
6. Recheck zero calibration as directed in Step 4. Repeat Steps 4 and 5 if
necessary.
C. Printer Menu:
Selects the thermal printer operating mode, printer scale, or
initiates printing of the previous run chart. Select the desired item
using the Enter and Back keys and change the selected parameter
using the 5/6 keys. Exit the menu using the Back key.
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