Confuse about esp32 3.3V and 0-30V from electric meter S0 pulse interface

pubsub
Posts: 2
Joined: Thu Mar 28, 2024 2:16 pm

Confuse about esp32 3.3V and 0-30V from electric meter S0 pulse interface

Postby pubsub » Thu Mar 28, 2024 2:33 pm

I just try a project to counting pulse signal from electric meter.
I was found a schematic from this guy . He pull-up digital pin to 3.3V VCC then connect to S0+, gnd from esp to S0-https://community.home-assistant.io/t/p ... ace/650061
Image

but as I read from https://sbc-support.com/uploads/tx_srcp ... .1_01.pdf the S0 interface pulse can reach max 15V or 27V . Can esp32 with 3.3V ttl tolerance this brutal volt? And if above schematic wrong what schematic I should follow

ESP_Sprite
Posts: 9052
Joined: Thu Nov 26, 2015 4:08 am

Re: Confuse about esp32 3.3V and 0-30V from electric meter S0 pulse interface

Postby ESP_Sprite » Fri Mar 29, 2024 1:54 am

An S0 connector itself does not output a voltage; the levels in that document specify what voltage you can apply to it externally without it breaking. Technically applying 3.3V is outside the specs (it says minimum is 5V) but I imagine it works with most meters anyway.

pubsub
Posts: 2
Joined: Thu Mar 28, 2024 2:16 pm

Re: Confuse about esp32 3.3V and 0-30V from electric meter S0 pulse interface

Postby pubsub » Fri Mar 29, 2024 2:41 am

ESP_Sprite wrote:
Fri Mar 29, 2024 1:54 am
An S0 connector itself does not output a voltage; the levels in that document specify what voltage you can apply to it externally without it breaking. Technically applying 3.3V is outside the specs (it says minimum is 3.3V) but I imagine it works with most meters anyway.
Thank you a lot . Now I'm brave enough to connect them.

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