Client-side IQC method for high precision sensors

First of all, we define the standard of high precision current sensor, the accuracy is greater than 0.1%, the linearity is about 0.1, which is called high precision current sensor, of course, there is a high precision current sensor with 1PPM accuracy.

The sensor with more than 0.1% accuracy is generally not based on Hall principle. The linearity of Hall can be very high, but the overall accuracy of 0.1% cannot be achieved. General high precision current sensor is the fluxgate principle of the current sensor. It is also the main means to achieve extremely high precision measurement.

Client-side IQC method for high precision sensors

Fluxgate high precision current sensor although the precision is very high, but the price is also very high, so the inspection and confirmation of the product is very necessary.

As a sensor producer, the calibration of current sensors is also extremely difficult, general manufacturers are not qualified, more than 0.1% of the sensor, generally with the help of the third party calibration, which is one of the main reasons for the high price.

If it is so difficult for the manufacturer, it is even more difficult for the client to accept the product. Here is a simple test method.

For example, to test a 10PPM high precision current sensor, theoretically must have more than 10PPM precision DC or AC source, 10PPM precision multimeter, which is generally not available.

In the inspection and test, the main high precision current within 10A can be added, the best is to add the current below 1A, in five and a half, or six and a half microampere to see whether the output of the current sensor is stable in a certain range.

That is to say, no matter how load current precision, as long as the stability, load current as small as possible, through the stability of the sensor output can be basic to determine whether a sensor for high precision sensors and, of course, this value should not be too small, * is well above the current 100 ma, if too small, magnetic induction amount is less than the geomagnetic too much, can't decide.

In practice, if you want to reflect the accuracy advantage of about 10PPM, the best way is through the zero calibration or linear calibration of MCU. But the premise of all this is that the sensor output must be stable, must be guaranteed to be fluxgate in principle.

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