Power over Modbus help - ultrasonic water meter

I picked up this ultrasonic water meter and can’t find a 3.3v UART to RS485 that lets you feed 12v-24v DC over Modbus… anyone done this and can share the module they used?

Doesn’t exist.
Maybe confused with MBUS?

Spec PDF.

Ok, I agree, but it’s out of RS485 standard.
And that water meter needs that?

I use a Belden 4 core cable for my modbus network. One pair for signal, the other pair for power (currently around 9V DC).

This is a standard, just newer. Can’t do 4 wire, i tried giving 12v on the RS485 pins, that did nothing.

It’s not a standard, just implementation, that’s why you don’t use standard hardware.
You can see on TI design note that you need to use modulation like FSK or Manchester.

When I ordered it, I thought it was RS485/Modbus on 2 conductors and 2 for power… as I had never seen this either. Should I get another one? If so, anyone got one working?

But your device has DC input and RS485/Modbus, it’s not like this one right?

You need datasheet for communication. I have municipal ultrasonic water meter with multiple wireless communications, non rechargeable battery for 15 years.
Your aliexpress page tells “Built in lithium battery (3.6V, 19ah)”. Only hell knows how you communicate with that if you don’t have further info…

I was confusing Modbus with MBUS… it had 2 conductors for MBUS that also provided 12v power. The Modbus was over RS485 conductors. Their documentation was horrible.