Fail grade: A, complete failure, can not continue to use; <br>B, lower accuracy, downgrade; <br>C, after repair, restore function; <br>D, the instrument is normal, testers to test the wrong way.
Failure level: A, completely invalid, can not continue to use;<br> B, the accuracy is reduced, the use of degradation;<br> C, after repair, restore function; D, the instrument is normal, the tester test method error.
Failure level: A. complete failure, unable to continue to use;<br>B. accuracy is reduced and degraded;<br>C. recover the function after repair;<br>D. the instrument is normal, and the tester's test method is wrong.<br>