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buchner-engelbrecht avatar image
buchner-engelbrecht asked

Victron BMV Shunt - what internal a/d converter used?

Can someone point me in the direction of where I can find out what bit number a/d converter is used in the BMV shunt? I hear rumors that it's a 12-bit converter, but I can't find any real info.

BMV Battery MonitorSmartShunt
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buchner-engelbrecht avatar image buchner-engelbrecht commented ·

In other words, I want to know exactly how accurate these shunts are. Yes I know it’s supposed to be accurate to +-0.4%, with a resolution of 0.1, but how fine does the analog to digital converter do it’s sampling? If it’s a 12 bit converter, it will have 4096 samples, which gives a 122mA per sample. Does that sound correct to anyone? Or do they use a different kind of A/D converter?

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wkirby answered ·

The BMV uses a very nice MSP430 with 24bit Sigma-Delta ADCs.

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buchner-engelbrecht avatar image buchner-engelbrecht commented ·
Thank you wkirby! Any chance you have a link or pdf that specify that it’s indeed a 24 bit adc?
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wkirby avatar image wkirby ♦♦ buchner-engelbrecht commented ·

1662195304280.png

MSP430F6733A datasheet here: https://www.ti.com/lit/ds/symlink/msp430f6733a.pdf?ts=1662192694836&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FMSP430F6733A


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buchner-engelbrecht avatar image buchner-engelbrecht wkirby ♦♦ commented ·

My apologies for stating my question a bit weird, I meant that do you have any documentation that specify that the BMV indeed uses the MSP430? I’d love it to be true, I just need to make sure please

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wkirby avatar image wkirby ♦♦ buchner-engelbrecht commented ·

I don't have any official documentation of course, but I can see it with my eyes.

pxl-20220903-093846957mp.jpg

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buchner-engelbrecht avatar image buchner-engelbrecht wkirby ♦♦ commented ·
Ahaa, thanks! You wouldn’t happen to know if the new smart shunt (without the screen) use the same chip?
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wkirby avatar image wkirby ♦♦ buchner-engelbrecht commented ·
Sorry, I don't know about the SmartShunt. I would think that even if it is a different microcontroller there would be no compromise on the ADC's resolution.
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