Model 100E Instruction Manual
Theory Of Operation
045150102 Rev XB1
177
The core of the analyzer is a microcomputer that controls various internal processes,
interprets data, makes calculations, and reports results using specialized firmware
developed by T-API. It communicates with the user as well as receives data from and
issues commands to a variety of peripheral devices through a separate printed circuit
assembly to which the CPU is mounted: the motherboard.
The motherboard is directly mounted to the rear panel and collects data, performs signal
conditioning duties and routs incoming and outgoing signals between the CPU and the
analyzer’s other major components.
Concentration data of the M100E are generated by the photo multiplier tube (PMT),
which produces an analog current signal corresponding to the brightness of the
fluorescence reaction in the sample chamber. This current signal is amplified to a DC
voltage signal (front panel test parameter
PMT
) by a PMT preamplifier printed circuit
assembly (located on top of the sensor housing).
PMT
is converted to digital data by a
bi-polar, analog-to-digital converter, located on the motherboard.
In addition to the PMT signal, a variety of sensors report the physical and operational
status of the analyzer’s major components, again through the signal processing
capabilities of the motherboard. These status reports are used as data for the SO
2
concentration calculation (e.g. pressure and temperature reading used by the
temperature/pressure compensation feature) and as trigger events for certain warning
messages and control commands issued by the CPU. They are stored in the CPU’s
memory and, in most cases, can be viewed through the front panel display.
The CPU communicates with the user and the outside world in a variety of ways:
•
Through the analyzer’s keyboard and vacuum fluorescent display over a clocked,
digital, serial I/O bus using the I
2
C protocol (pronounced “I-squared-C”);
•
RS 232 & RS485 serial I/O channels;
•
Various analog voltage and current outputs and
•
Several digital I/O channels.
Finally,
the CPU issues commands (also over the I
2
C bus) to a series of relays and
switches located on a separate printed circuit assembly, the relay board (located in the
rear of the chassis on its own mounting bracket) to control the function of key
electromechanical devices such as heaters that keep the sample chamber at a steady
temperature and, when installed, the zero/span and internal zero/span valve sets and
heaters.
10.4.1.
CPU
The CPU is a low power (5 VDC, 0.8A max), high performance, 386-based microcomputer
running the DR-DOS operating system. Its operation and assembly conform to the
PC-104 specification, version 2.3 for embedded PC and PC/AT applications. It has 2 MB of
DRAM memory on board and operates at 40 MHz clock rate over an internal, 32-bit data
and address bus. Chip to chip data handling is performed by two 4-channel direct
memory access (DMA) devices over data busses of either 8-bit or 16-bit bandwidth. The
CPU supports both RS-232 and RS-485 serial protocols. Figure 10-11 shows the CPU.
Summary of Contents for 100E
Page 2: ...Model 100E Instruction Manual ...
Page 4: ...Model 100E Instruction Manual ii 045150102 Rev XB1 ...
Page 12: ...Model 100E Instruction Manual x 045150102 Rev XB1 ...
Page 20: ...M100E Documentation Model 100E Instruction Manual 18 045150102 Rev XB1 User Notes ...
Page 26: ...Specifications Approvals and Warranty Model 100E Instruction Manual 24 045150102 Rev XB1 ...
Page 46: ...Getting Started Model 100E Instruction Manual 44 045150102 Rev XB1 User Notes ...
Page 128: ...Operating Instructions Model 100E Instruction Manual 126 045150102 Rev XB1 User Notes ...
Page 156: ...EPA Protocol Calibration Model 100E Instruction Manual 154 045150102 Rev XB1 ...
