Processor Board: The processor board is the smaller of the two printed
circuit boards and contains the Intel 80C186EB central processor, two
flash EPROM’s, RAM, Realtime clock, watchdog circuit, and glue
logic.
Application Board: The application board contains the circuits for con-
trolling and interfacing with the other subsystems such as the keypad,
display, 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.
Power Supply
The power supply converts AC voltage supplied via the AC cord into
one or more lower DC voltages for use by the electronics and cooling
system.
Sampler (Figure 3)
The sampler is a specialized pipette which contains and positions a very
specific volume of sample for each test. The sampler consists of the
pipette body, plunger wire, and disposable plastic sampler tip that must
be replaced after each test.
Operating cradle (Figure 3)
The operating cradle is a sliding mechanism that guides and introduces
the sampler to the freezing chamber.
Cooling chamber & measurement and control circuits:
A high-reliability thermoelectric module controls cooling chamber tem-
perature, while a thermistor sample probe measures the dynamic tem-
perature of a sample. Test results, based on the freezing point of the
sample, are automatically sent to the instrument’s display.
User Interface (Figure 7)
The user interface consists of a display and a two-button keypad. The
display will typically provide information on the first line, and identify
the button functions on the second line. In general, the left button will
9
Instrument Operation
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