Teledyne 2020 - Explosion proof thermal conductivity analyzer - Manual (Page 48)

4 Operation Model 2020
4-14 Teledyne Analytical Instruments
TER settling, before it can go back to Analyze . Software zero is indicated
by
S–Zero in the lower right corner.
####.## % H2 — N2
4 Left=#.### S—Zero
The zeroing process will automatically conclude when the output is
within the acceptable range for a good zero. Then the analyzer automatical-
ly returns to the
Analyze mode.
4.4.1.2 Manual Mode Zeroing
Scroll to Zero and enter the Zero function. The screen that appears
allows you to select between automatic or manual zero calibration. Use the
UP/DOWN keys to toggle between
AUTO and MAN zero settling. Stop when
MANUAL appears, blinking, on the display.
Select zero
mode: MANUAL
Enter to begin the zero calibration. After a few seconds the first of
three zeroing screens appears. The number in the upper left hand corner is
the first-stage zero offset. The microprocessor samples the output at a
predetermined rate.
####.## % H2 — N2
Zero adj:2048 C—Zero
The analyzer goes through C–Zero, F–Zero, and S–Zero. During C–
Zero and F–Zero, use the UP/DOWN keys to adjust displayed
Zero adj:
value as close as possible to zero. Then, press Enter .
S–Zero starts. During S–Zero, the Microcontroller takes control as in
Auto Mode Zeroing, above. It calculates the differences between successive
samplings and displays the rate of change as
Slope= a value in parts per
million per second (ppm/s).
####.## % H2 — N2
Slope=#.### S—Zero
Generally, you have a good zero when
Slope is less than 0.05 ppm/s for
about 30 seconds.
Once zero settling completes, the information is stored in the analyz-
er’s memory, and the instrument automatically returns to the Analyze
mode.