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Operating Instructions Teledyne API Model T360/T360M Operation Manual
96
4.8.1. Physical Range versus Analog Output Reporting Ranges
Functionally, the Gas Filter Correlation CO
2
Analyzer has one hardware Physical
Range that is capable of determining CO
2
concentrations between 50 ppm and
2,000 ppm. This architecture improves reliability and accuracy by avoiding the
need for extra, switchable, gain-amplification circuitry. Once properly calibrated,
the analyzer’s front panel will accurately report concentrations along the entire
span of its 50 ppm and 2,000 ppm physical range.
Because, most applications use only a small part of the analyzer’s physical range,
the width of the Model T360’s physical range can create data resolution problems
for most analog recording devices. For example, in an application where the
expected concentration of CO
2
is typically less than 500 ppm, the full scale of
expected values is only 25% of the instrument’s 2,000 ppm physical range.
Unmodified, the corresponding output signal would also be recorded across only
25% of the range of the recording device.
The T360 solves this problem by allowing the user to select a scaled reporting
range for the analog outputs that only includes that portion of the physical range
relevant to the specific application. Only the reporting range of the analog
outputs is scaled, the physical range of the analyzer and the readings displayed on
the front panel remain unaltered.
4.8.2. Reporting Range Modes
The T360 provides three analog output range modes to choose from.
Single range (SNGL) mode sets a single maximum range for the analog
output. If single range is selected (see Section 4.8.3) both outputs are
slaved toge
ther and will represent the same measurement span (e.g. 0-50
ppm), however their electronic signal levels may be configured for different
ranges (e.g. 0-10 VDC vs. 0-.1 VDC – see Section 4.13.4).
Dual rang
e (
DUAL) allows the A1 and A2 outputs to be configured with
different measurement spans (see Section 4.8.4) as well as separate
electronic sig
nal levels (see Section 4.13.4).
Auto rang
e (
AUTO) mode gives the analyzer to ability to output data via a
low range and high range. When this mode is selected (see Section 4.8.5)
the T360 will automatically swit
ch between the two ranges dynamically as the
concentration value fluctuates.
Range status is also output via the external digital I/O status outputs (see Section
4.15.1).
07272B DCN6552