Teledyne 3020T User Manual
Page 46
4 Operation
Model 3020T
4-10
Teledyne Analytical Instruments
Although the instrument can be spanned using air, a span gas with a
known oxygen concentration in the range of 70–90% of full scale of the
range of interest is recommended. Since the oxygen concentration in air is
209,000 ppm, the cell can take a long time to recover if the instrument is
used for trace oxygen analysis immediately following calibration in air.
Connect the calibration gases to the analyzer according to the instruc-
tions 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 (ap-
proximately 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 Zero Cal
The
ZERO
function on the MAIN MENU is used to enter the zero
calibration function. Zero calibration can be performed in either the auto-
matic or manual mode. In the automatic mode, an internal algorithm com-
pares consecutive readings from the sensor to determine when the output is
within the acceptable range for zero. In the manual mode, the operator
determines when the reading is within the acceptable range for zero.
Make sure the zero gas is connected to the instrument.
If you get a
CELL FAILURE message skip to section 4.8.1.3.
4.8.1.1
Auto Mode Zeroing
Select
ZERO
to enter the
ZERO
function. The
ZERO
screen allows
you to select whether the zero calibration is to be performed automatically or
manually. Use the DOWN/UP control to toggle between
AUTO and MAN
zero settling. Stop when
AUTO appears on the display.
Zero: Settling: AUTO
<ENT> To Begin
ENTER to begin zeroing.
#### PPM Zero
Slope=#### ppm/s