Connecting to 2 Eastron SDM120 Modbus Meters

@glyn.hudson - that might be worth noting and adding to the docs. I’d also add the above information to the Docs as well re ID and Baud rate.


OK. All messages read, though probably not fully received. You are dealing with a half-wit…
I’ve checked and the baud rate is set to 2800 (I’ve seen now that one can change it but let’s not…that’s power user material).
I’ve managed to change the set the meters to id 1 and 2.
As to daisy-chaining… D’oh. That makes perfect sense but it may have to wait until the weekend as I’ll need to alter the wiring that I carefully shrink-wrapped for extra tidiness…
Thank you all. More thrills and spills guaranteed.



Perhaps you meant to say 2400?

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The weekend has arrived and I’ve had a good fiddle! It WORKS!

For anyone wanting the play by play action, I set the addresses on the Eastrons to 1 and 2. Baud was
set to 2400 (rather than any other semi-random number ending in zero @Bill.Thomson :roll_eyes:). The two meters are daisy-chained and then out to a single RS485 adapter, along with their two earth/ground wires. With the EmonPi switched off, the adapter was then plugged into one of the four USB ports. When I turned things back on I pasted @glyn.hudson 's code into the config file and restarted the Hub. And now we have a torrent of numbers for meters a and b coming out of the SDM120s.
I attach a photo which, with deep gratitude I humbly submit under a CC-everything license to help another ignorant peasant to hook up their meters in the future.

[Alt text: two daisy-chained power meters side-by-side showing how where the wires run from the A and B terminals]

I owe several people multiple glasses of a cleansing ale (or equivalent refreshment). I’m thirsty already.