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Teledyne 6000B - Photometric analyzer User Manual

Page 51

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Photometric Analyzer

Operation 3

Part I 3-25

Teledyne Analytical Instruments

3.6.2 Auto Screen

Autoranging will automatically set to the application that has at least two

ranges setup with the same gases.

In the autoranging mode, the microprocessor automatically responds to

concentration changes by switching ranges for optimum readout sensitivity. If the
upper limit of the operating range is reached, the instrument automatically shifts
to the next higher range. If the concentration falls to below 85% of full scale of
the next lower range, the instrument switches to the lower range. A correspond-
ing shift in the DC concentration output, and in the range ID outputs, will be
noticed.

The autoranging feature can be overridden so that analog output stays on a

fixed range regardless of the contaminant concentration detected. If the concen-
tration exceeds the upper limit of the range, the DC output will saturate at 1 V dc
(20 mA at the current output).

However, the digital readout and the RS-232 output of the concentration

are unaffected by the fixed range. They continue to read beyond the full-scale
setting until amplifier saturation is reached. Below amplifier saturation, the
overrange readings are accurate UNLESS the application uses linearization over
the selected range.

The concentration ranges can be redefined using the

Range

function

Manual screen, and the application gases can be redefined using the

System

function, if they are not already defined as necessary.

CAUTION: Redefining applications or ranges might require

relinearization and/or recalibration.

To setup automatic ranging:

Press

Range

key to start the Range function.

Select

range

mode : AUTO

If above screen displays, use the

Δ∇ arrow keys to Select AUTO, and

press

Enter.

Press

Escape

to return to the previous Analyze Function.