Why there are gas pressure differential manometers with 1 Pa resolution, but the barometric absolute pressure ones with only 10 Pa (0.1 mBa)resolution ?
Probably because for barometric pressure 10Pa is very little (~100,000 Pa atmospheric pressure).
have you researched every manufacturer in the world? It seems a bold statement to claim something doesn't exist for sure.
I meant there seems to be no one being shown or sold in internet. Must be very expensive (however, if a usual relative pressure manometer is not - why an absolute pressure one should be ?)
any device's accuracy depends on the total scale. a manual manometer (or sensor) that measures 0-10 Pa will be accurate to 0.1 Pa. A manometer measuring 100,000 Pa, will only be accurate to 100 Pa etc. So measuring differential pressure,t eh pressure you measure is not so great. but absolute pressure will be large since you add the ~100,000 Pa atmospheric pressure. Now as i explained above, having 1 Pa resolution on a device measuring 100,000+ Pa, will be very costly.
Know the difference between accuracy and precision. but in general if you want high precision (1 Pa0 this only makes sense with high accuracy, which cost $.
I think what HerrKaLeun is trying to explain is that the accuracy of a "good" gauge is typically 1% of its full-scale reading. A "very good" gauge might be 0.5% and a "crappy" one 5%.
So for a "good" gauge with a range of 0 - 100,000 Pa 1% of 100,000 = 1,000. That means that for whatever number you read on the gauge the actual value might be 500 Pa higher or lower than the reading.
If you read 98,532 Pa the true value lies between 98,032 and 99,032.
If you read 1,275 Pa the true value is between 775 and 1,775.
If you read 10 Pa the true value is between -490 and 510
If you read 1 Pa the true value is between -499 and 501
Hopefully you can see the pointlessness of reporting a value of 1 ± 500 Pa
