Electronic balance error of calculation and analysis
Source of information：Shanghai Yueping Date：2016/7/31
As a very precise electronic balance, electronic instruments, mainly used in laboratory, research fields such as chemical industry research institute. Although electronic balance than other weighing instruments precision is more high, but for laboratory researcher, very small error can lead to the failure of the experiment, so often said the lab to the error of electronic balance is calculated and analysed.
The error analysis of the electronic balance in two situations:
, e indicates 1 d, the calculation formula of error should be e = I - L (e: electronic balance, of error I: balance indicated value, L the balance plate loaded lotus);
2, when e = d, the calculation formula of error should be e = I - L (1/2) d - delta L (d: AL: electronic balance scale dividing actual value in the electronic balance tray for rounding and add value for load). Either way, require the income of each load point error is less than the procedures stipulated in the margin of error.
Repetitive verification: electronic balance, electronic balance repetitive verification should be done under no-load and load condition, the load of load has two kinds: one kind is full load, a male child. Requirement of load and no-load test of equilibrium position for reading and record, at the same time pay attention to each add a load all should return zero one time. For the same load measure the difference between the results for many times, shall not exceed the balance in the absolute value of the maximum permissible error when the load.
Electronic balance partial verification (four error verification) : for a standard of electronic balance, the test load is equal to the biggest weighing electronic balance, the corners of the error is equal to the minimum value minus maximum value. For working with electronic balance, the test load is equal to one third of the maximum load balance, its error is equal to the value for each point in the four corners and center of the difference between the value of the largest.
Electronic balance taring function check: the electronic balance should be examined for new purchase its counter balance function, generally choose two loading points, namely: (1/3) Max, Max (2/3). The difference between the two results obtained under the same load value, shall not exceed the maximum permissible error when the load of the absolute value.
Electronic balance in the verification problems need attention: how to select standard weight? Selection criteria weights can be weights, also can be such as weight, but it's error (such as for level weight tolerance for quality, for weight verification accuracy) shall not be greater than the checked electronic balance under the load of a third of the maximum permissible error. Second, the standard weight range can cover to the biggest weighing electronic balance.
Second, the standard weight range can cover to the biggest weighing electronic balance.
Electronic balance exempted from inspection problems:
(1) when the electronic balance of mg in d 1 or less, can be exempted from inspection the electronic balance discrimination;
(2) when the e indicates d electronic balance, can be exempted from inspection the electronic balance discrimination;
(3) with digital indicator and automatic or semi-automatic calibration device of electronic balance, the balance can be exempted from inspection sensitivity. Calibration certificate shall be issued by standardization: electronic balance after the verification, issue the certificate of verification or calibration verification results should be based on the actual result slip. The author thinks that the certificate is issued by a very serious and shall bear legal responsibility, first format specification, the content should cover the GJB2725-96, all of the information of the elements of the "4.1", the results of calibration (verification) or test should be accurate and objective.
