Teledyne 3000ZA, Operating Instructions Manual

Page: 53 / 81

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 M
ANUAL
M
ODE
Z
EROING
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 C
ELL
F
AILURE
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