Accuracy is defined as the conformity of an indication to its true value. Accuracy is a percentage of the full range. For example, a gauge that has a scale of 0-300 psi with an accuracy of ±1% would mean that the gauge is accurate to within ± (plus or minus) 3 psi.
Accuracy Grade - ASME B40.1 (American Society of Mechanical Engineers)
Accuracy grade |
Lower 1/4 of scale |
Middle 1/2 of scale |
Upper 1/4 of scale |
4A |
0.1 |
0.1 |
0.1 |
3A |
0.25 |
0.25 |
0.25 |
2A |
0.5 |
0.5 |
0.5 |
1A |
1 |
1 |
1 |
A |
2 |
1 |
2 |
B |
3 |
2 |
3 |
C |
4 |
3 |
4 |
D |
5 |
5 |
5 |
|