Teledyne 3010TB - Split architecture trace oxygen analyzer - Manual (Page 41)

Oxygen Analyzer Part I: Control Unit
Part I: 4-13
Teledyne Analytical Instruments
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
Δ∇ 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 prede-
termined 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. Slope is
given in ppm/s.
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 span settling completes, 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 3010TB is usually associated with inability to zero
the instrument down to a satisfactorily low ppm reading, e.g. cell does not
fail if it comes below 5PPM . When this occurs, the 3010TB system alarm
trips, and the LCD displays a failure message.
#.# ppm Anlz
CELL FAIL/ ZERO HIGH
Before replacing the cell:
a. Check your span gas to make sure it is within specifications.
b. Check for leaks downstream from the cell, where oxygen may be
leaking into the system.