SMA Speedwire python interpreter

speedwire.py

# SMA Speedwire interpreter
#
# This little script interprets SMA's speedwire as multicasted from the Sunny Home Manager 2
# and will print out the energy flow total, and for each phase

import socket
import struct

MULTICAST_IP = "239.12.255.254"
MULTICAST_PORT = 9522

sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind(("", MULTICAST_PORT))

mreq = struct.pack("4sl", socket.inet_aton(MULTICAST_IP), socket.INADDR_ANY)

sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)

# def print_with_offsets(data):
#    # For debugging: prints out the datastream in hex
#    i = 0
#    datasize = len(data)
#    while i < datasize:
#        print(str(i) + ": " + data[i:i+10].hex())
#        i = i+10


def decode_phase_chunk(data, phase):
    # This is given just a single chunk of phase data
    total_buy = data[6:8]
    print(phase + "  buy: " + str(int.from_bytes(total_buy, byteorder="big") / 10))
    total_sell = data[26:28]
    print(phase + " sell: " + str(int.from_bytes(total_sell, byteorder="big") / 10))


def decode_speedwire(data):
    # Taken from https://www.sma.de/fileadmin/content/global/Partner/Documents/SMA_Labs/EMETER-Protokoll-TI-en-10.pdf
    # print_with_offsets(data)
    SMA = data[
        0:3
    ]  # This is just the identifier of the packet, should start with "SMA\0"
    sysUid = data[4:7]
    serialNumber = data[20:24]
    print(
        "SMA: "
        + str(SMA)
        + " sysUid: "
        + str(sysUid)
        + " Serial: "
        + str(serialNumber.hex())
    )

    total_power_buy = data[34:36]
    total_power_sell = data[54:56]
    print("A:  buy: " + str(int.from_bytes(total_power_buy, byteorder="big") / 10))
    print("A: sell: " + str(int.from_bytes(total_power_sell, byteorder="big") / 10))

    decode_phase_chunk(data[164:308], "L1")
    decode_phase_chunk(data[308:452], "L2")
    decode_phase_chunk(data[452:596], "L3")


while True:
    decode_speedwire(sock.recv(10240))

This is for home automation or whatever you want to repurpose it for. SMA's Home Manager 2.0 will broadcast on the multicast address (always 239.12.255.254) the values once per second. This script will output this once per second:

SMA: b'SMA' sysUid: b'\x00\x04\x02' Serial: abcdefg
A:  buy: 2842.9
A: sell: 0.0
L1  buy: 2706.9
L1 sell: 0.0
L2  buy: 235.1
L2 sell: 0.0
L3  buy: 0.0
L3 sell: 99.1

A is the total, and L1/L2/L3 are on each phase.

Thanks, I used the information from your script to implement a daemon for my home automation that publishes those values to a MQTT server.
What really puzzles me though is why I receive null values for some minutes after the connect, before the real measured values follow, did you also encounter this behavior?

Hi Sean, not sure how successful this will be in asking for your help. I’m
A newbie electronics hobbyist from UK and ideally wanted a steer on getting my nodemcu esp8266 with Tasmota working to read counter inputs. I’m trying to create a sensor to read my gas meter and add to HA. I’ve a bit stuck to be honest, any help with be appreciated please and I’ll buy you a coffee. :-)

Thanks, I used the information from your script to implement a daemon for my home automation that publishes those values to a MQTT server. What really puzzles me though is why I receive null values for some minutes after the connect, before the real measured values follow, did you also encounter this behavior?

It turned out that this problem only happened as long as my SMA Tripower wasn't connected to the solar panels yet. Yesterday it got connected and now it's not an issue anymore, very strange🤷‍♂️

Here's my finished script which also reports the kWh's: https://github.com/vindolin/sma2mqtt

Hi,
wie hast du denn in deinem Projekt "Gaszähler" den Wemos an den Impulszähler angeschlossen.

Gruuß Torsten