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edge540
I am working on my uncertainty budget for a 1m long calibration device for testing machine crosshead travel and long stroke extensometers. Basically I want to express the U as a percent of reading. So far everything is absolute in um... so I'm a bit stuck.
I have had the instrument calibrated and they give a +/- 5um uncertainty to the device.
Resolution is 1um.
I calculated through a repeatability study appx 15um for the std dev. and then introduced a cosine error and came up with appx 23um for that std. dev.
In the end I calculate about a 27um Uncertainty... but I would rather express it as a % of reading.
I'm not too clear on how to do that though.
If this question has been asked (and it is probably buried here somewhere) I apologize in advance.
Any help is appreciated.
I have had the instrument calibrated and they give a +/- 5um uncertainty to the device.
Resolution is 1um.
I calculated through a repeatability study appx 15um for the std dev. and then introduced a cosine error and came up with appx 23um for that std. dev.
In the end I calculate about a 27um Uncertainty... but I would rather express it as a % of reading.
I'm not too clear on how to do that though.
If this question has been asked (and it is probably buried here somewhere) I apologize in advance.
Any help is appreciated.