Teledyne 7300a - NDIR analyzer - Manual (Page 61)

Infrared Gas Analyzer Operation 4
4-25 Teledyne Analytical Instruments
range 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 APPLICA-
TION function, if they are not already defined as necessary.
CAUTION: Redefining applications or ranges might require re-
linearization and/or recalibration.
To setup automatic ranging:
Select range on the MAIN MENU, and ENTER to start the Range func-
tion.
Select range
mode : AUTO
Note: If all three ranges are currently defined for different applica-
tion gases, then the above screen does not display (because
mode must be manual).
If above screen displays, use the UP/DOWN key to Select
AUTO, and
Enter.
Press Escape to return to the previous Analyze Function.
4.6.3 Precautions
The Model 7300A 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: