Teledyne 3000ZA - Trace oxygen analyzer - Manual (Page 51)

Trace Oxygen Analyzer Operation
Teledyne Analytical Instruments 39
TRAK/HLD Auto—Cal
PSWD Logout More
Use the __ arrow keys to blink More , then press Enter.
Version Self—Test
Show_Negative=NO
Use the __ arrow keys and select “ Show_Negative = NO”.
Use the __ arrow keys to toggle from NO to YES.
Press the Escape key twice to return to the analyze mode.
This preference is stored in non-volatile memory so the
configuration is remembered after a power shutdown. If the instrument
is cold started, it will go back to the default case where negative oxygen
readings are not shown.
4.4 The Zero and Span Functions
Zeroing is not required in order to achieve the published accuracy
specification of this unit however, zeroing will eliminate offset error
contributed by the sensor, electronics and the internal and external
sampling systems. It will improve performance beyond published
specification limits.
The analyzer is calibrated using zero and span gases.
Any suitable oxygen-free gas can be used for zero gas as long as it
is known to be oxygen free and does not react adversely with the sample
system.
A span gas with a known oxygen concentration in the range of
70–100% of full scale of the range of interest is recommended. In the 0-
10 ppm range, 8 ppm span gas would be best suited.
Connect the calibration gases to the analyzer according to the
instructions given in Section 3.3.1, 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 0.1 and 2.4
SLPM (approximately 0.2 - 5 SCFH).