Teledyne BDS-3000 - Oxygen analyzer User Manual
Page 65
Oxygen Analyzer
Operation
Teledyne Analytical Instruments
51
#### PPM
Zero
Slope = ####
ppm/s
The beginning zero level is shown in the upper left corner of the
display. As the zero reading settles, the screen displays and updates
information on slope (unless the slope starts within the acceptable zero
range and does not need to settle further).
Then, and whenever slope is less than 0.08 for at least 3 minutes,
instead of slope you will see a countdown: 5 Left, 4 Left, and so fourth.
These are five steps in the zeroing process that the system must
complete, AFTER settling, before it can go back to Analyze.
#### PPM
Zero
4 Left = ###
ppm/s
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.
Because the reading of the slope is not very sensitive, it is
recommended that zero gas be purging a few minutes before starting the
Auto mode zeroing. This will ensure cell stability on the new Zero
settings.
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
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