Trace Oxygen Analyzer Operation
Teledyne Analytical Instruments 41
The zeroing process will automatically conclude when the output is
within the acceptable range for a good zero. Then the analyzer
automatically returns to the Analyze mode.
4.4.1.2 MANUAL MODE ZEROING
Press Zero to enter the Zero function. The screen that appears
allows you to select between automatic or manual zero calibration. Use
the __ keys to toggle between AUTO and MAN zero settling. Stop when
MAN appears, blinking, on the display.
Zero: Settling: Man
<ENT> To Begin
Press Enter to begin the zero calibration. After a few seconds the
first of five 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. 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).
#### ppm Zero
Slope=#### ppm/s
Note: It takes several seconds for the true Slope value to display.
Wait about 10 seconds. Then, wait until Slope is
sufficiently close to zero before pressing Enter to finish
zeroing .
Generally, you have a good zero when Slope is less than 0.05
ppm/s for about 30 seconds. When Slope is close enough to zero, press
Enter. In a few seconds, the screen will update.
Once zero settling is completed, the information is stored in the
microprocessor, and the instrument automatically returns to the Analyze
mode.
4.4.1.3 CELL FAILURE
Cell failure in the 3000ZA is usually associated with inability to
zero the instrument down to a satisfactorily low ppm reading. When this
occurs, the instrument will still Zero, but the 3000ZA system alarm
trips, and the LCD displays a failure message.
#.# ppm Anlz