DV-POWER - Support

Micro Ohmmeter - Accuracy statement

The accuracy of our Micro Ohmmeters is defined as ±(0,2% rdg + 0,2% FS) provided the following two conditions are met:

the measurement current is at least 100A
the measurement range is between 100µΩ and 20mΩ

If the current is below 100A the accuracy can be established following the table below:

Test current	Error
50 A	0,25%+1µΩ
20 A	0,5%+2µΩ
10 A	1%+5µΩ

Measurement of specimens below 100µΩ is not recommended with current below 100A.

For specimen with resistance between 20µΩ and 100µΩ the accuracy is defined following the table below:

Test current	Error
600 A	0,2%+0,5µΩ
500 A	0,2%+0,6µΩ
400 A	0,2%+0,7µΩ
300 A	0,2%+0,8µΩ
200 A	0,2%+0,9µΩ
100 A	0,2%+1,0µΩ

For specimen with resistance above 20mOhm accuracy is defined using table:

Test current	Error
50 A	0,25%
20 A	0,5%
10 A	1%

If you need a higher accuracy, then you need to:

verify instrument calibration using provided Test Shunt before testing
always use the max current available for particular range*
do two measurement in two directions, the second measurement with inverted connection on the VS input. Calculate the average of the two measurements.

*Max current for a given range depends on the supply voltage, length and cross section of cables (cable resistance), and max measurement range on the Voltage sense input. Max measurement range on the Voltage sense input is 2,5V

In case the instrument cannot reach/generate pre-set test current, display will show the value of the maximum current achieved and the result. This result is of the lower accuracy, so we recommend that this test is repeated pre-selecting the first lower current range.

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