Thunder Scientific 2500 series, Руководство по эксплуатации и обслуживанию

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1.4.2 Central Processing Unit (STD-CPU)
The Central Processing Unit consists of a 64180 micro-processor, along with all supporting
hardware required to interface with the other devices. During the humidity generation
process, the main processing unit executes programming designed to control the parameters
needed to generate relative humidity, such as pulsing heaters and operating valves. Virtually
all functions of the system are controlled by this Central Processing Unit which is responsible
for system timing, user interfacing, information display, and parameter control.
1.4.3 Liquid Crystal Display (LCD)
The display incorporated into the 2500 humidity generator is a backlit, 256 x 128, dot matrix
Liquid Crystal Display (LCD). It is used for the purpose of displaying system information
such as setpoints, measurements, and any other information pertinent to the operation of the
2500 humidity generator.
1.4.4 Liquid Crystal Display Driver (STD-LCD)
The Liquid Crystal Display Driver (STD-LCD) receives display commands and data from the
Central Processing Unit then converts these into the signals required to drive the Liquid
Crystal Display module. It also incorporates a voltage inversion circuit, which co5
VDC input to a -21 VDC output required by the LCD module.
Contrast adjustment is controlled via a 0 to -5 VDC analog output from the STD-CPU. The
variable voltage is fed by a single wire from the STD-CPU to the STD-LCD driver board.
This voltage level, and the resulting contrast, is adjusted by the user from the front panel
keypad. (See section 3.2.2.1)
1.4.5 Keypad
The 4 x 4 Keypad provides operator input to the 2500 humidity generator. The keypad is
used to select modes of operation from the menus, enter humidity and temperature points for
humidity generation, and perform any other interface functions where user input is required.
During operation, most of the screens will show four rectangular shaped blocks at the right
side of the display. These blocks correspond with four blank keys on the left side of the
keypad, which will be used to perform various functions within the program.
1.4.6 Memory Card (STD-MEM)
The Memory Card contains both EPROM and battery backed memory. This memory
contains all program and data required for operation of the generator.
1.4.7 Analog to Digital Converter (STD-A/D)
The Analog to Digital Converter board is a 15 bit analog to digital converter, with integral
signal conditioning, used to monitor thermistor resistance, pressure transducer voltage, and
flowmeter voltage. It has a useable voltage range of 0 to +5 VDC.