Teledyne 3020T, Operating Instructions Manual, Page: 58 / 85

Trace Oxygen Analyzer Operation
Teledyne Analytical Instruments
45
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.
Connect the calibration gases to the analyzer according to the
instructions given in section 3.5,
Gas Connections
, observing all the
prescribed precautions.
Shut off the gas pressure before connecting it to the analyzer,
and be sure to limit the pressure to 40 psig or less when turning it
back on.
Readjust the gas pressure into the analyzer until the flowrate (as
read on the analyzer’s SLPM flowmeter) settles between 0.5 and 2.4
SLPM (approximately 1-5 scfh).
If you are using password protection, you will need to enter your
password to gain access to either of these functions. Follow the
instructions in section 4.4 to enter your password. Once you have gained
clearance to proceed, you can ENTER the
ZERO
or
SPAN
function.
4.8.1.3 C
ELL
F
AILURE
Cell failure in the 3020T is usually associated with inability to zero
the instrument down to a satisfactorily low ppm reading. When this
occurs, the 3020T system alarm trips, and the LCD displays a failure
message.
#.# ppm Anlz
CELL FAIL/ ZERO HIGH
Before replacing the cell:

Check for leaks downstream from the cell, where oxygen may be
leaking into the system.

Check your span gas to make sure it is within specifications.