El Cheapo II
- Thread starter Warhammer
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Warhammer The Relentless,
You can calibrate with any known source--air, even in Mississippi--is a known source. However, for nearly every measuring device known to man, it is better to calibrate it with something that is about the same as what you are measuring. This is because most properties and/or measuring devices are not completely linear.
I am not expert on how critical it is to know whether your O2 is 34% or 32%, but if it is critical, it would be best to use a sample in the range that you want to measure. Oh yeah, and remember what I wrote a long time ago about air samples--do not take them close to stack or other device that might be richer in CO2, etc.
Okay?
Joewr
You can calibrate with any known source--air, even in Mississippi--is a known source. However, for nearly every measuring device known to man, it is better to calibrate it with something that is about the same as what you are measuring. This is because most properties and/or measuring devices are not completely linear.
I am not expert on how critical it is to know whether your O2 is 34% or 32%, but if it is critical, it would be best to use a sample in the range that you want to measure. Oh yeah, and remember what I wrote a long time ago about air samples--do not take them close to stack or other device that might be richer in CO2, etc.
Okay?
Joewr
Iguana Don
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There are only 2 companies that manufactur the sensors for O2 analyzers. Other than that they are all pretty much identical. A circuit to translate the digital readings. Some sites that have plans to build your own.
ID
ID
Ok, I get your point. Critical? It can be, depending on the conditions, but +/- 1% is generally acceptable.
Guys,
Good thread. Since I don't mix my gas, I use my analyzer as a doublecheck to what is provided to me. If there is a discrepancy between what the mix is logged and what my analyzer is reading then I want to sort it out.
I have heard stories about everyone relying on the same analyzer to verify mix. If that analyzer is off, noone knows. All analyzers are calibrated against the ambient air every use. I check my analyzer periodically against various mixes upto and including 100% O2 to verify the sensor and analyzer readings.
If this is inadequate, your suggestions and comments are appreciated.
I have found the "Oxygen Hacker's Companion" to be an excellent resource. It is chock full of good information.
DSAO
Good thread. Since I don't mix my gas, I use my analyzer as a doublecheck to what is provided to me. If there is a discrepancy between what the mix is logged and what my analyzer is reading then I want to sort it out.
I have heard stories about everyone relying on the same analyzer to verify mix. If that analyzer is off, noone knows. All analyzers are calibrated against the ambient air every use. I check my analyzer periodically against various mixes upto and including 100% O2 to verify the sensor and analyzer readings.
If this is inadequate, your suggestions and comments are appreciated.
I have found the "Oxygen Hacker's Companion" to be an excellent resource. It is chock full of good information.
DSAO
Daylight,
And that is exactly why one needs to calibrate against a known standard regularly--as you wisely do! Believing blindly in a machine is trouble!
I remember reading a guage that had the same reading hour after hour after hour... That seemed unlikely to me--so I did a "manual calibration"--I tapped with my finger--and it moved 30%! Turned out it was stuck! Take home lesson: always be just a little sceptical about machines, meters, etc.--especially when your life depends on them. Calibration against a known standard is one way to do that.
I think Warhammer is a budding chemical engineer...
Joewr
And that is exactly why one needs to calibrate against a known standard regularly--as you wisely do! Believing blindly in a machine is trouble!
I remember reading a guage that had the same reading hour after hour after hour... That seemed unlikely to me--so I did a "manual calibration"--I tapped with my finger--and it moved 30%! Turned out it was stuck! Take home lesson: always be just a little sceptical about machines, meters, etc.--especially when your life depends on them. Calibration against a known standard is one way to do that.
I think Warhammer is a budding chemical engineer...
Joewr
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