Greisinger Oxy 3690 Oxygen Meter 602951 Data Sheet
Product codes
602951
T02.0.4X.6C-09
page 5 of 6
Appendix B: oxygen sensor
General information about the oxygen sensors
I.) Lifetime:
At the end of life time the sensor signal drops relatively fast. The electrode evaluation in % therefore just can be used for
orientation. An evaluation of 70% does not mean that 70% of life time are remaining, but 70% of the reference signal are
available, which happens normally at the end of life time.
At the end of life time the sensor signal drops relatively fast. The electrode evaluation in % therefore just can be used for
orientation. An evaluation of 70% does not mean that 70% of life time are remaining, but 70% of the reference signal are
available, which happens normally at the end of life time.
Note: The electrode evaluation is updated by the instrument every time, when the calibration of the sensor was performed
successfully.
(please also see the referring manual of the instrument)
The nominal life time can be shortened significantly by usage. Influencing factors are:
- Storage- / Operation temperature
- Humidity of measured gas: If permanently used with dry gases (technical gases, bottled gas) the life time decreases
considerably.
It helps, if the sensor is brought to normal humid ambient air in measuring breaks (“flush” system with fresh air).
It helps, if the sensor is brought to normal humid ambient air in measuring breaks (“flush” system with fresh air).
II.) Operating position:
The optimum operation position is with the sensor inlet pointing downwards, maximum differential pressure to ambient is
250 mbar.
The optimum operation position is with the sensor inlet pointing downwards, maximum differential pressure to ambient is
250 mbar.
III.) Measuring precision:
The measuring precision can be influenced by:
The measuring precision can be influenced by:
- Liquids at the sensor inlet. Rinse the inlet and dry with lint-free cloth.
Attention: avoid liquids of any kind at the contacts
- Gas and sensor temperature have to be at same level. Best precision, when calibrated at measuring temperature.
- Pressure fluctuations: The sensor is originally a partial pressure sensor, i.e. changes in the absolute pressure are influencing
the measuring result directly proportional. A pressure change of 1% will cause a additional measuring error of 1%!
For optimum precision calibrate at the same conditions at which You want to measure.
For optimum precision calibrate at the same conditions at which You want to measure.
Application of the different sensor types GGO... /MU (standard) and GOO... / MU (option)
GGO... (closed sensor)
For measurements at atmosphere and in systems without over or under pressure the GGO is sufficient. Additionally the
GGO can be screwed impermeable to systems with low over or under pressure.
Attention! If the sensor cannot be calibrated at exactly the same pressure, the measurement will be faulty! For such appli-
cations we have integrated a manual pressure compensation. Then the GGO can be connected to systems with a known
pressure (Attention: please note the specified operating pressure for one-sided strain). The pressure can be entered to
the device an will compensated by the device such no additional measuring error will occur.
For measurements at atmosphere and in systems without over or under pressure the GGO is sufficient. Additionally the
GGO can be screwed impermeable to systems with low over or under pressure.
Attention! If the sensor cannot be calibrated at exactly the same pressure, the measurement will be faulty! For such appli-
cations we have integrated a manual pressure compensation. Then the GGO can be connected to systems with a known
pressure (Attention: please note the specified operating pressure for one-sided strain). The pressure can be entered to
the device an will compensated by the device such no additional measuring error will occur.
GOO... (open sensor)
The sensor is equipped with drillings at the end and because of its special construction the measuring gas streams opti-
mally around the sensor. No pressure can appear while gas blows to the sensor, which otherwise would result in errone-
ous measures.
The temperature compensation speed of the sensor also is optimised by this design. The measuring gas escapes into the
air. Especially the measuring of gases from compressed gas bottles, where the expansion of the gas leaving the bottle
lowers the temperature, is optimised with regard to the temperature compensation and pressure errors. The gas flow
should be chosen in a suitable range, where no overpressure can happen, esp. if the sensor is connected directly to the
source e.g. by means of a tube.
The sensor is equipped with drillings at the end and because of its special construction the measuring gas streams opti-
mally around the sensor. No pressure can appear while gas blows to the sensor, which otherwise would result in errone-
ous measures.
The temperature compensation speed of the sensor also is optimised by this design. The measuring gas escapes into the
air. Especially the measuring of gases from compressed gas bottles, where the expansion of the gas leaving the bottle
lowers the temperature, is optimised with regard to the temperature compensation and pressure errors. The gas flow
should be chosen in a suitable range, where no overpressure can happen, esp. if the sensor is connected directly to the
source e.g. by means of a tube.
Oxygen measuring notes
Calibration and measuring are depending of the absolute pressure at the sensor.
Therefore check the absolute pressure before calibration and measuring.
Therefore check the absolute pressure before calibration and measuring.
Sensor temperature and gas temperature should be the same.
Temperature differences may cause additional measuring errors! In worst case conditions it may take up to several hours
until both temperatures are adjusted. A suitable flow of the gas around the sensor element increases the adjustment sig-
nificantly.
Temperature differences may cause additional measuring errors! In worst case conditions it may take up to several hours
until both temperatures are adjusted. A suitable flow of the gas around the sensor element increases the adjustment sig-
nificantly.