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Energy metering with BL0937 on self made smart switch relay

andrejesus

Aug 3, 2023
2
Joined
Aug 3, 2023
Messages
2
Hi all! First post on the forum!

I'm trying to make my one smart switch with relays and ESP32.
I Wold like to also add a power metering capabilities to it, like we have in some shellys.

Found out that Shellys use this IC for power metering: BL0937
datasheet: https://www.belling.com.cn/media/file_object/bel_product/BL0937/datasheet/BL0937_V1.02_en.pdf

First two questions:
- Are the L and N wires inverted in the schematics shown in the datasheet?
- It is shown in the schematics a connection from the Live wire to Ground? Witch ground? Should we connect our Live AC wire to our electronics Ground?

Other findings that make this even more confusing:
There is another similar IC HLW8012 but it uses 5v instead of 3.3v
Datasheet rev1.3: https://ez.analog.com/cfs-filesyste...omponents-files/138/HLW8012-_2800_1_2900_.pdf
Datasheet rev1.4: https://datasheet.lcsc.com/lcsc/1811151452_Hiliwei-Tech-HLW8012_C83804.pdf

In rev 1.3 schematics are pretty similar but in rev1.4 the L and N wires were inverted?!
Does this mean that the BL0937 is also wrong?
And last question: If the L and N connection are inverted will it be ok to connect our electronics Grounding to the Neutral wire? Will it be appropriate to add some fuses to this?

Thank you all for the help.
 
Last edited:

sgodblacktechy

Jul 27, 2023
11
Joined
Jul 27, 2023
Messages
11
Watch out for inverted wires, and be cautious with Live wire connections to Ground. Safety first!
 

Bluejets

Oct 5, 2014
7,097
Joined
Oct 5, 2014
Messages
7,097
Sounds like, with your inexperience, you are about to grow wings or get handed a pitchfork.
 

andrejesus

Aug 3, 2023
2
Joined
Aug 3, 2023
Messages
2
Yes you can call it inexperience, thats why im asking for help in the forum.
Who knows, may be I can pull something out of this, even within failure there is always something to learn.
Let's hope I grow some wings!
 
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