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Operational Theory 2
During calibration, the microcontroller on the main board stores
information regarding zero and full span values. Specifically, the
microprocessor takes a series of consecutive readings and calculates the
difference between pairs of consecutive readings. The embedded software
analyzes the resulting differences and tests for discrepancies in the result.
The microprocessor uses this information to test for drift during
calibration.
The absolute difference between a true zero and 100% span gas is
determined at the factory and permanently stored in memory. The
software compares this value with collected data during a calibration or
measurement to determine the validity of the reading. If the calibration or
sample gas measurement falls outside a predetermined range based on the
known good values in memory, error routines are called and signals are
sent to the display board to generate appropriate messages. See Section 5
Calibration for more information.
2.3.4 Display
The display contains the 2-line 16 character vacuum fluorescent
display on the front panel. Signals are transferred to and from the main
board via a ribbon cable.
2.3.5 I/O Board
The standard I/O board is responsible for taking a analog signal from
the main board and converting it to a 0–1, 0–5 or 0–10 V analog output.
An optional 4–20 mA isolated current ouput may be installed depending
on the options selected by the customer. See Section 3.7.1.
2.4
Sample System
If a sample system is not provided by LSC, the customer will be
responsible for providing a suitable sample system. A custom sample
system can be designed and fabricated by LSC based on the particular
application. Contact Teledyne Analytical Instruments for details.
In order to achieve maximum results from the analyzer, some
consideration must be given to the sample system design. The sample
system is responsible for supplying properly conditioned sample and
calibration gases to the analyzer at a pressure and flow rate commensurate
with the analyzer. The sample system provided by the customer must be
capable of delivering clean and moisture free (non-condensing) sample to
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Teledyne Analytical Instruments., - Rev. 3
IR7000
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