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In a circuit I'm developing I have a shunt that is used for current measurement of +/- 80A. How can its calibration be done? Suppose our budget for this can be 1000 to 1500 USD, what would be the best way to do this?

One option I was thinking is using a current sensor with digital output like the 100A version of ICD series current sensor with CAN output. Run a power supply with different loads and based on the reading from this sensor calibrate the shunt.

[Update] This is for a manufacturing jig. Calibration up to 0.2% accuracy of shunt value would help.

What other ways can work better?

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    \$\begingroup\$ It seems fairly simple. Four point measurement (apply certain voltage, use volt meter and amp meter to accurately measure voltage and current) and record the exact resistance. \$\endgroup\$
    – TQQQ
    Aug 28, 2023 at 15:56
  • \$\begingroup\$ Calibration, to what standard? Your cal equipment costs could vary by several orders of magnitude depending on whether you want traceability to national standards, or 0.1%, or 1%, or 10% advertised accuracy. Specify what you really need. \$\endgroup\$
    – Neil_UK
    Aug 28, 2023 at 16:17
  • \$\begingroup\$ You are looking for a one-off calibration or for a calibration rig to calibrate series production of this circuit for something like an energy meter to a recognized standard? Your budget seems very low if it is the latter. \$\endgroup\$ Aug 28, 2023 at 23:00
  • \$\begingroup\$ I've added the accuracy requirement and application. \$\endgroup\$
    – EarthLord
    Aug 29, 2023 at 5:24

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It depends the accuracy you need.

The most accurate solution is to send it in a decent calibration lab. They have the expertise and the tool to do measurements in that order of magnitude accurately. It is most likely way cheaper then to do the calibration by yourself.

If you want to do it by yourself, the first question you should ask yourself is what do you define as calibration. Do you only want to measure it, or you also want to adjust it. What temperature and humidity will it be exposed to. How frequent the calibration should be done? How exact does your shunt need to be? How stable does your shunt need to be? How many shunt will you need to calibrate? And so on.

If you are considering a current sensor with a nominal 0.8% accuracy, I think you would be best served by a 6.5 digit multimeter with a precise 4 wire measurement. I would consider either the DMM6500 from Keithley or 34465A from Keysight. Both will be easy to keep their calibration and can be used for quite a lot in an electrical lab. Consider that any tools you will use will need to be on a calibration schedule to ensure accuracy over several years.

If you need more accuracy then this, your best option will be to use an 8.5 digit DMM. This scenario is WAY more expensive then your budget.

If you want to use any sensor, since they are cheaper, you might get good accuracy, but you'll have a hard time knowing for sure. You will also have difficulties getting them calibrated. So tracking their accuracy over time will be almost impossible.

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  • \$\begingroup\$ Thanks. I'll add test points for the kelvin connection in the PCB layout for the SMD shunt to be able to do the 4 wire measurement. \$\endgroup\$
    – EarthLord
    Aug 29, 2023 at 5:25
  • \$\begingroup\$ I'm sure you know that, but in circuit ohm measurement aren'.t accurate. Ensure you have a series break to disconnect it from the rest of your circuit to prevent interference during the measurement. \$\endgroup\$
    – Julien
    Aug 29, 2023 at 13:35

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