KeepItSimpleStupid
- Joined Mar 4, 2014
- 5,088
@danadak Thanks a bunch for "taking over' this thread.
I was just saying is that if you need 0.5mV out of 20 mV, then you only need to count to 20/0.5 or 40.
And at 40 counts, the +- error is a lot less than at 1 count.
The PGA can more effectively resolve 0.5 mV when say 1 mV is 400 counts. (made up numbers)
I guess, in the process world say 0-1000 deg. +-0.5 degrees is the accuracy of say the thermocouple, but maybe we only care how close it is to 300 deg,
12 bits might be able to resolve an instrument that can measure -200 to 2000 degrees.
A blood pressure cuff doesn;t need a gazillion digits. Neither does it make any sense generally to know if its 25 or 25.00003 degrees. Is it 13 kV or 13.1 kV? We don't care if it's 13,0001.001 V
Then there was the vacuum gauge with decade outputs 0-1, 1-2, 2 to 3 up to 10 V out.
was like 1e-3, 1e-4, 1e-5, 1e-6 torr.
I was just saying is that if you need 0.5mV out of 20 mV, then you only need to count to 20/0.5 or 40.
And at 40 counts, the +- error is a lot less than at 1 count.
The PGA can more effectively resolve 0.5 mV when say 1 mV is 400 counts. (made up numbers)
I guess, in the process world say 0-1000 deg. +-0.5 degrees is the accuracy of say the thermocouple, but maybe we only care how close it is to 300 deg,
12 bits might be able to resolve an instrument that can measure -200 to 2000 degrees.
A blood pressure cuff doesn;t need a gazillion digits. Neither does it make any sense generally to know if its 25 or 25.00003 degrees. Is it 13 kV or 13.1 kV? We don't care if it's 13,0001.001 V
Then there was the vacuum gauge with decade outputs 0-1, 1-2, 2 to 3 up to 10 V out.
was like 1e-3, 1e-4, 1e-5, 1e-6 torr.
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