Teledyne 6600 - Manual (Page 50)

3 Operation Model 6600
3-26 Part I
Teledyne Analytical Instruments
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:
Enter the Range function to start the Range function.
Select range
mode : AUTO
If above screen displays MAN, use the UP/DOWN switch to Select
AUTO, and Enter.
Press Escape to return to the previous Analyze Function.
3.6.3 Precautions
The Model 6600 allows a great deal of flexibility in choosing ranges for
automatic range switching. However, there are some pitfalls that are to be
avoided.
Ranges that work well together are:
• Ranges that have the same lower limits but upper limits that differ
by approximately an order of magnitude
• Ranges whose upper limits coincide with the lower limits of the
next higher range
• Ranges where there is a gap between the upper limit of the range
and the lower limit of the next higher range.
Range schemes that are to be avoided include:
• Ranges that overlap