4.2
Span Calibration using a Certified Span Gas
Calibration involves using a known span gas to match and adjust the oxygen sensor / ana-
lyzer combo to a known value. This can be as simple as using ambient air that tends to be a
constant 20.9% or a bottle of certified span gas from your local air separation company. For
this section, we will focus on using a certified span gas from your local air separation com
-
pany. When using a certified bottle, it is recommended to get a span gas equal to 90% of the
range you want to use. If you are measuring in the 0 - 1000 ppm range, a 900 ppm N2 /
balance oxygen would be ideal.
For a decision on which type of calibration is good for your process, consult the factory for a
recommendation.
Calibration using Certified Span Gas:
It is recommended to read through the calibration prior to performing
an air calibration to ensure all instructions are understood. Consult
the factory if any questions arise.
Note: For a new trace oxygen sensor (TO2-133 or TO2-233), purging with a
zero gas for 4 - 6 hours will help the low end stability and response. This
is not necessary on a percent or purity sensor.
Connect the gas sample line and set the pressure / flow per section 2.4
of the users manual.
Once the gas is flowing, let the reading stabilize for about 5 - 10 minutes
and then proceed (Consider longer if sensor is still trending).
SPAN CALIBRATION: To calibrate the indicator, press MENU key
Use UP/DOWN keys to bring cursor besides the option SPAN
CAL and press the ENTER key.
Use the UP / DOWN key until the reading on the display matches
the value of your SPAN Gas. For example if your SPAN gas is 80.2ppm
adjust the display UP or DOWN until it reads 80.2ppm.
Once ENTER has been pressed, the display will show “PASSED” or
“FAILED”. If passed, promptly put the sensor in a zero or low oxygen
gas. This will help extend the life of the sensor and speed of response.
If failed, repeat calibration steps or consult the factory.
Trace Oxygen Sensor Caution: The sensor should be exposed to ambient
air for less than 2 minutes. This will help speed of response, sensor life
and low end sensitivity.
Maintenance
OMD-625 Oxygen Analyzer
Designed, Tested and Assembled in California, USA
4045 E. Guasti Rd. #203 Ontario, CA 91761 USA : 1-949-398-2879 : [email protected] : www.sso2.com
20.5%
UP - INCREASE
DOWN - DECREASE
ENTER TO CAL
ESC TO EXIT
MAIN MENU
AUTO RANGE
MANUAL RANGE
SPAN CAL
ZERO CAL
ALARM 1
ALARM 2
SYSTEM
