battery-connector.py

#!/usr/bin/env python

"""Fetches and sets the fronius battery charging
power in % via modbus.
Inspired by Juraj's battsett.jar."""

import paho.mqtt.client as paho  # pip install paho-mqtt
import time
import logging
import sys
from config import *

from pymodbus.constants import Endian
from pymodbus.payload import BinaryPayloadDecoder
from pymodbus.client.sync import ModbusTcpClient as ModbusClient


def battery_data():

    values = {}

    # Datentypen der Register "float32","uint64","uint16"
    #    'string': decoder.decode_string(8),
    #    'float': decoder.decode_32bit_float(),
    #    '16uint': decoder.decode_16bit_uint(),
    #    '8int': decoder.decode_8bit_int(),
    #    'bits': decoder.decode_bits(),

    client = ModbusClient(MODBUS_HOST, port=502)
    client.connect()

    r = client.read_holding_registers(40327 - 1, 2, unit=1)
    inWRte = BinaryPayloadDecoder.fromRegisters(r.registers, byteorder=Endian.Big) # noqa E501

    values['chg_pct'] = inWRte.decode_16bit_uint() / 100
    logging.debug("From modbus chg_pct {}%".format(values['chg_pct']))

    client.close()

    return values


def on_message(mqttc, obj, msg):
    if msg.topic == "{}/set/chg_pct".format(BATTERY_MQTT_PREFIX):
        newValue = int(msg.payload) * 100
        client = ModbusClient(MODBUS_HOST, port=502)
        client.connect()
        client.write_register(40327 - 1, newValue, unit=1)
        client.close()

        logging.debug("Setting via modbus chg_pct: {}".format(newValue)) # noqa E501

        update()


def update():
    values = battery_data()
    for k, v in values.items():
        (result, mid) = mqttc.publish("{}/{}".format(BATTERY_MQTT_PREFIX, k), str(v), 0, retain=True) # noqa E501
        logging.info("Pubish Result: {} MID: {} for {}: {}".format(result, mid, k, v)) # noqa E501


if __name__ == '__main__':
    logging.basicConfig(stream=sys.stdout,
                        format='%(asctime)s %(levelname)-8s %(message)s',
                        datefmt='%Y-%m-%d %H:%M:%S',
                        level=logging.INFO)

    mqttc = paho.Client('battery-connector', clean_session=True)
    # mqttc.enable_logger()
    mqttc.will_set("{}/connectorstatus".format(BATTERY_MQTT_PREFIX), "Battery Connector: LOST_CONNECTION", 0, retain=True) # noqa E501

    mqttc.connect(BROKER_HOST, BROKER_PORT, 60)
    logging.info("Connected to {}:{}".format(BROKER_HOST, BROKER_PORT))

    mqttc.publish("{}/connectorstatus".format(BATTERY_MQTT_PREFIX), "Battery Connector: ON-LINE", retain=True) # noqa E501

    mqttc.on_message = on_message
    mqttc.subscribe("{}/set/chg_pct".format(BATTERY_MQTT_PREFIX), 0)

    mqttc.loop_forever()