Python script to read SDM630 power meter and publish to mqtt

sdm630_to_mqtt.py

#!/usr/bin/python
import minimalmodbus
import paho.mqtt.client as mqtt
import paho.mqtt.publish as pub

# RS485 serial settings
DEVICE="/dev/ttyUSB0"
SLAVE=2
DEBUG=False
FUNCODE=4
REG_NO=2

# MQTT settings
MQTT_HOST="localhost"
MQTT_PORT=1883
MQTT_TOPIC="power/sdm630/{}/".format(SLAVE)

REGISTERS = {
    "L1_Voltage": 0,
    "L2_Voltage": 2,
    "L3_Voltage": 4,
    "L1_Current": 6,
    "L2_Current": 8,
    "L3_Current": 10,
    "L1_L2_Voltage": 200,
    "L2_L3_Voltage": 202,
    "L3_L1_Voltage": 204,
    "L1_Active_Power": 12,
    "L2_Active_Power": 14,
    "L3_Active_Power": 16,
    "L1_Apparent_Power": 18,
    "L2_Apparent_Power": 20,
    "L3_Apparent_Power": 22,
    "L1_Reactive_Power": 24,
    "L2_Reactive_Power": 26,
    "L3_Reactive_Power": 28,
    "L1_Power_Factor": 30,
    "L2_Power_Factor": 32,
    "L3_Power_Factor": 34,
    "L1_Phase_Angle": 36,
    "L2_Phase_Angle": 38,
    "L3_Phase_Angle": 40,
    "L1_Current_THD": 240,
    "L2_Current_THD": 242,
    "L3_Current_THD": 244,
    "Total_System_Power": 52,
    "Total_System_VA": 56,
    "Total_System_VAR": 60,
    "Total_System_Power_Demand": 84,
    "Total_System_Power_Demand_Max": 86,
    "Total_System_VA_Demand": 100,
    "Frequency": 70,
    "Import_Active_Energy": 72,
    "Export_Active_Energy": 74,
    "Import_Reactive_Energy": 76,
    "Export_Reactive_Energy": 78,
    "Total_Active_Energy": 342,
    "Total_Reactive_Energy": 344,
}


def setup_serial():
    # serial port setup
    rs485 = minimalmodbus.Instrument(DEVICE, SLAVE)
    rs485.serial.baudrate = 9600
    rs485.serial.bytesize = 8
    rs485.serial.parity = minimalmodbus.serial.PARITY_NONE
    rs485.serial.stopbits = 1
    rs485.serial.timeout = 1
    rs485.mode = minimalmodbus.MODE_RTU
    rs485.debug = False
    if DEBUG:
        print("Serial port settings: {}".format(rs485))
    return rs485


def read_register(serial, reg):
    value = serial.read_float(reg, FUNCODE, REG_NO)
    if DEBUG:
        print("Register Value read is: {}".format(value))
    return value


def publish_values(values):
    for reg_name, reg_val in values.items():
        if DEBUG:
            print("Publising register {}={} to MQTT".format(reg_name, reg_val))
        pub.single(MQTT_TOPIC + reg_name, "{0:.1f}".format(reg_val), qos=2, hostname=MQTT_HOST, port=MQTT_PORT, client_id="sdm630_mqtt")



# main logic
print("Start")
values = {}
rs845 = setup_serial()

print("Reading of SDM630 registers started...")

for reg_name, reg_no in REGISTERS.items():
    if DEBUG:
        print("Dealing with register: {} [register={}]".format(reg_name, reg_no))
    reg_val = read_register(rs845, reg_no)
    values[reg_name] = reg_val

print("Reading of SDM630 registers finished, {} items.".format(len(values)))
print("Publising values to MQTT...")

publish_values(values);

print("End")