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Instrument Operation
Measurement and control circuits (inside)
The microprocessor-controlled circuits automatically measure and
control the dynamic temperature of the sample freezing chamber.
Process calibration data and sample temperature information. They also
present calibrated test results on the digital display.
Electronic circuits (inside)
The main circuitry is contained on two printed circuit boards in a
motherboard/daughter board configuration. More in depth technical
details are available in the unit service manual sold separately.
Processor Board: The processor board is the smaller of the two printed
circuit boards and contains the Intel 80C186EB central processor, two
flash EPROMs, RAM, Realtime clock, watchdog circuit, and glue logic.
Application Board: The application board contains the circuits for
controlling and interfacing with the other subsystems such as the
keypad, display, head motor, cooling assembly, RS-232, printer and
barcode ports, etc. The application board also contains two 20-bit A/D
converters for reading the sample and block probe thermistors.
Display panel (Figure 3, Item 4)
The display panel displays:
• Test status and results.
• Status messages when the instrument is turned on or when
functions are selected.
• Pertinent error messages when fault conditions occur. (Messages
longer than 20 characters scroll across display.)
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