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Teledyne 7300a - NDIR analyzer User Manual

Page 56

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4 Operation

Model 7300A

4-20

Teledyne Analytical Instruments

ENTER will move the blinking field to units (%/ppm). Use UP/DOWN key

to select the units, as necessary. When you have set the concentration of the
span gas you are using,

Enter

to begin the Span calibration.

####.##% CO2

Slope=#.### Span

The beginning span value is shown in the upper left corner of the display.

As the span reading settles, the screen displays and updates information on
Slope. Spanning automatically ends when the span output corresponds, within
tolerance, to the value of the span gas concentration. Then the instrument auto-
matically returns to the analyze mode.

4.4.2.2

Manual Mode Spanning

Scroll Span by using UP/DOWN key and Enter to start the Span function.

The screen that appears allows you to select whether the span calibration is to
be performed automatically or manually.

Select span

mode: MANUAL

Use the UP/DOWN key to toggle between

AUTO and MAN span setting.

Stop when

MAN appears, blinking, on the display. ENTER to move to next

subfunction screen

Span Val: 2Ш.ШШ %

To begin span

Using the UP/DOWN key changes the span value, as necessary.

Enter

to

move to the units field (%/ppm). Use UP/DOWN key to select unit.

Press

Enter

to enter the span value into the system and begin the span

calibration.

Once the span has begun, the microprocessor samples the output at a

predetermined rate. It calculates the difference between successive samplings
and displays this difference as Slope on the screen. It takes several seconds for
the first Slope value to display. Slope indicates rate of change of the Span
reading. It is a sensitive indicator of stability.

####.##% CO2

Slope=#.### Span

When the

Span value displayed on the screen is sufficiently stable, press

Enter

. (Generally, when the

Span reading changes by 1 % or less of the range

being calibrated for a period of ten minutes it is sufficiently stable.) Once

Enter