Current Monitor/Shunt

Theoretically its possible, but the code would need to be changed to cater for the 16 bit device. I don’t have any plans to make these changes at the present time.

Yes, that’s what I did… I paid 150€ for 2 chips now :frowning:

Cheaper option, but still $21 - pull the INA228 off this board Power Monitor Click

I tried that aswell, but they can only deliver mid-November

Can I use ADM2483BRWZ instead of ADM2483xRW?
There are no differences in the catalog card.

Hi, i am not an expert, but… what about an opamp (high impedance) in the shunt of the pzem017 detecting only the “signal” of the voltage shunt (between -75mv to 75mv).

I mean, we only want to detect negative voltages in the shunt, so after that, esp32 could add “negative” sign to current and power. Of course, we could not use the energy values of the pzem as they will be wrong if we have negative values in current.

I have also read about using an optocoupler for detecting negative voltages, but I can’t find any schematic.

We need another pin in the esp32 to read the opamp output.

Will an opamp disturb the circuit of the measurement of the shunt voltage of the pzem?

@stuart @ross @Bill.Thomson @atanisoft what do you think?

ADDED: For example here I can find a solution:
https://www.ti.com/lit/ds/symlink/opa388.pdf?ts=1662872968696
Point 8.2.1 Bidirectional Current-Sensing
Do you think that with an input current bias of pA it will disturb the pzem circuit?

Hi, anybody? @stuart probably you know much more than me. Do you think if this is possible? Could we “check” the current sign without disturbing the PZEM-017 measurement ?
Thanks.

I’ve not actually taken at look at the internal working of the PZEM017, I purely interfaced with it over the RS485. The way its built doesn’t support current flow polarity detection, not sure if that can be overcome.

I have read that it supports flow in both directions, but, as you say, it always return a positive value

But the value is real. So if we could find any solution “to detect” the polarity/sign of the flow, it will be a great improvement.

But I am not a “circuit expert”. :pensive:

Is there anyone here that knows how to do this?