Measure more than 200a with ACS758

[Yaroooo]

Can I measure more than 200A with ACS758?

Here's a double module:
https://www.aliexpress.com/item/32862321547.html?spm=a2g0o.productlist.0.0.533f4161T3cdXE&algo_pvid=89f0b4fb-0d97-43a0-8015-0b1dd155d876&algo_exp_id=89f0b4fb-0d97-43a0-8015-0b1dd155d876-20&pdp_ext_f=%7B%22sku_id%22%3A%2265361047982%22%7D

Each is 200A load. My rated current is 150A with possible 300A short peak. I'd like to measure also this peaks. Is possible to connect this two sensors in parallel (two separate wire from source to load) and then sum the read current from both?

[T3sl4co1l]

You can use a current divider.  Connect the load through two shunt resistors in parallel.  The current divides between them according to their resistances: I1 / I2 = R2 / R1 (where I1 is the current through R1, etc.).  Or out of the total, I1 = I * R2 / (R1 + R2).  Wire the sensor in series with one of the resistors.  (Note that sensor and wiring resistance must be summed with the resistor to get the true result.)

The tricky part is, wiring and contact resistances will all affect the result, at least unless you use relatively large shunt resistors (~mΩ?).  Note also that wire has a strong tempco, so the balance will also drift as temperature changes.  The tradeoff is how much power you can afford to dissipate in the resistors, versus how good of a match you need.

Tim

[fcb]

In theory, you could put two in parallel (back-back) and then rescale one of the outputs to give 0-400A. 

You would essentially be using one of the two as a pure shunt, you could possibly (invert one of them) and sum them to get a little lower noise/range - perhaps. Probably do this in your sampling system.

There are thermal considerations possibly if you have them back-back at continuous high currents, also the leadframe is copper so the TC (temperature coefficient) is poor. Not the way to go if you need great accuracy and linearity.

[Kleinstein]

Using 2 sensors in parallel does would, if the resistance is suitable to divide the current about equally between the 2 sensors. Separate cables can do the job, but make sure that worst case 1 cable could still stand the full current, just in case.

One should still measure both sensors and only than add he result. The exact ratio may change with temperature.

[Yaroooo]

You can use a current divider.  Connect the load through two shunt resistors in parallel.  The current divides between them according to their resistances: I1 / I2 = R2 / R1 (where I1 is the current through R1, etc.).  Or out of the total, I1 = I * R2 / (R1 + R2).  Wire the sensor in series with one of the resistors.  (Note that sensor and wiring resistance must be summed with the resistor to get the true result.)

The tricky part is, wiring and contact resistances will all affect the result, at least unless you use relatively large shunt resistors (~mΩ?).  Note also that wire has a strong tempco, so the balance will also drift as temperature changes.  The tradeoff is how much power you can afford to dissipate in the resistors, versus how good of a match you need.

Tim

I'd like to avoid use of shunts since on this currents they are very big. I've found the smallest one of 120mm x 35mm of 200++g (from aliexpress).

Thank for answers, I'll try to use them in parallel.