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November 24, 2013
Product SEN-09403 |
about 4 months ago
Here is a calibration gas source:
There are many others.
These sensors work in ‘open air’ environments only. So called “PURE” gas environments are not possible. Typical Oxygen mix PLUS the contaminant to check for.
Calibration is done in a sealed container, with a stirring fan. Find a large square tupperware bowl or small fish tank. Fit a tight lid to the tank. Fit a hose fitting to the lid, such that the sensor can be coupled to the tank. Fit a second hose fitting connected to a syrenge or small gas cylender. Apply a given gas and evaluate readings according to the data sheet. Before testing, be sure to run the fan with the lid OFF in order to mix the environment.
For example, 1CC of rubbing alcohol in a syrenge pumped into a tank of 1000CC volume, dropping in front of the fan, should quickly mix. Or use a bicycle/paintball gun CO tank.
In this case, calibrations are in reference to the typical atmosphere of the calibration location.
The purpose of the one time bake 12/24 hours) is to eliminate any remaining moisture or contamination from the manufacturing process. Remember that this sensor operates by the gas coming in contact with a doped ceramic coating (which the heater is embedded in). As for the voltage cycle/level.. I don’t know. I am making contact with Henwai. time is in the data sheet.
For readings, you need only bring the sensor up to temp and ‘burn off’ any new contaminants. Data sheet suggests a 3 minute heat time before taking a reading, followed by a cool down before taking another reading.
When operating outdoors, it is suggested that you run the heater all the time at a LOW power to keep it warm (above outdoors ambient/above freezing). This will keep it dry and prevent it from freezing. Moisture will affect readings. Fully wet or frozen will destroy the ceramic.
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