Teledyne 6000A Operating Instructions Manual page 51

Photometric Analyzer
operator control. The Set Range Screen of the System func-
tion allows the user to DEFINE the upper and lower limits of a
range AND the application of the range. The Range button
function only allows the user to select or define the limits, or
to select the application, but not to define the application.
Normally the Model 6000A is factory set to default to manual range
selection, unless it is ordered as a single-application multiple-range unit (in which
case it defaults to autoranging). In either case, autoranging or manual range
selection can be programmed by the user.
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.
To program the ranges, you must first perform the four steps indicated at
the beginning of section 3.8 Programming. You will then be in the second
System menu screen.
Use the < > arrow keys again to move the blinking to
press Enter .
Use the ∆∇ arrow keys to increment/decrement the range number to 01,
02, 03, or CAL, and press Enter .
Teledyne Analytical Instruments
Operation 3
and
Part I 3-27