Teledyne T200, Руководство по эксплуатации, Страница: 305 / 425

Teledyne API
– T200 NO/NO
2
/NO
X
Analyzer Operation Manual Principles of Operation
303
The core of the analyzer is a microcomputer/central processing unit (CPU) that controls
various internal processes, interprets data, makes calculations, and reports results using
specialized firmware developed by Teledyne API. It communicates with the user as
well as receives data from and issues commands to a variety of peripheral devices via a
separate printed circuit assembly onto which the CPU is mounted: the motherboard.
The motherboard is directly mounted to the inside rear panel and collects data, performs
signal conditioning duties and routes incoming and outgoing signals between the CPU
and the analyzer‟s other major components.
Data are generated by the sensor module which outputs an analog signal corresponding
to the amount of chemiluminescence present in the reaction cell. This signal is
converted into digital data by a unipolar, analog-to-digital converter, located on the
motherboard.
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 various concentration calculations and as trigger
events for certain warning messages and control commands issued by the CPU. This
information is stored in memory by the CPU and in most cases can be viewed by the
user via the front panel display.
The CPU issues commands via a series of relays and switches (also over the I
2
C bus)
located on a separate printed circuit assembly, called the relay PCA, to control the
function of key electromechanical devices such as heaters and valves. It also issues
some commands directly to the Sensor module (e.g. initiate Electric Test or Optical
Test).
By controlling the state of various valves the CPU directs the flow of sample gas
through the various gas paths of the analyzer (NO measurement path; NO
x
measurement
path; Auto Zero Path). Based on which path is active, the CPU interprets the sensor
output to derive raw data representing concentrations for NO
x
, NO and zero (dark
condition), accesses the operational data stored in memory then calculates final
concentrations for NO
x
, NO and NO
2
.
The CPU communicates with the user and the outside world in several ways:

Through the analyzer’s front panel LCD touch-screen interface

Through the serial I/O channels

Various analog voltage and current outputs

Several sets of Digital I/O channels

Ethernet
06858E DCN7057