Teledyne T101, Operation Manual, Page: 71 / 375

Teledyne ML – T101 Operation Manual Operating Instructions
67
AUTO mode, see section 4.4.4.6) or operate independently ( IND mode, see Section
4.4.4.5). The user may also select between a variety of reporting range spans as well:
EXAMPLE:
A1 OUTPUT: Output Signal = 0-5 VDC representing 0-1000 ppm concentration values
A2 OUTPUT: Output Signal = 0 – 10 VDC representing 0-500 ppm concentration
values.
NOTE
On analyzers with the SO
2
-H
2
S multigas measurement option installed the outputs of A1
and A2 correspond to:
Output SO
2
SO
2
– H
2
S H
2
S
Channel Mode Mode Mode
A1

SO
2

SO
2

H
2
S
A2

SO
2

H
2
S

H
2
S
As the instrument switches from H
2
S mode to SO
2
mode and back, only the reporting range and analog
output associated with the gas currently being measured will be active. The reporting range and analog
output for the gas no being measured will continue to report the last valid reading.
The output, labeled A4 is special. It can be set by the user (see Section 4.6.9) to output
many of the parameters accessible through the <TST TST> buttons of the units Sample
Display.
Output A3 is not available on the Model T101 Analyzer.
4.4.4.2. Physical Range versus Analog Output Reporting Ranges
The T101 UV Fluorescence H
2
S Analyzer has two hardware physical ranges that cover
H
2
S concentrations between 0 and 20,000 ppb. The low range is 0 to 2,000 ppb, while the
high range is 0 to 20,000 ppb. The proper physical range is determined by the software to
include the maximum measurement concentration selected by the user. Once properly
calibrated, the analyzer’s front panel will accurately report concentrations along the entire
span of its 0 and 20,000 ppb physical range.
Because, most applications use only a small part of the analyzer’s two physical ranges,
the width of the Model T101’s physical range can create data resolution problems for
most analog recording devices. For example, in an application where the expected
concentration of SO
x
is typically less than 500 ppb, the full scale of expected values is
only 0.25% of the instrument’s 20,000 ppb physical range. Unmodified, the
corresponding output signal would also be recorded across only 0.25% of the range of the
recording device.
The T101 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.