question

Any help would be appreciated!

Thanks

Mike

Sorry no answers here but it looks like we're both looking for the same or similar thing. I'm using VB6 and I want a MODBUS command string to get the MultiPlus to return the value, SOC, Solar Voltage and more but an answer on how to read just one register from someone out there would be great!

This will print out the status of the Battery.

wait two seconds and print it again.

Change the Unit ID and IP address to match your equipment (Only the BMV and the System ID are used in this example)

To install

pip install pymodbus

#!/usr/bin/env python3
 
# Modbus
from pymodbus.constants import Defaults
from pymodbus.constants import Endian
from pymodbus.client.sync import ModbusTcpClient as ModbusClient
from pymodbus.payload import BinaryPayloadDecoder
from pymodbus.payload import BinaryPayloadBuilder
from time import sleep
 
#===================================
 
# GX Device I.P Address
ip = '192.168.20.156'
client = ModbusClient(ip, port='502')
 
#===================================
 
# ModBus Unit ID
SolarCharger_1_ID = 226
SolarCharger_2_ID = 224
SolarCharger_3_ID = 239
MultiPlus_ID      = 227
Bmv_ID            = 223
VEsystem_ID       = 100
 
#===================================
 
def modbus_register(address, unit):
    msg     = client.read_input_registers(address, unit=unit)
    decoder = BinaryPayloadDecoder.fromRegisters(msg.registers, byteorder=Endian.Big)
    msg     = decoder.decode_16bit_int()
    return msg
 
while True:
 
    # Battery Section
    BatterySOC       = modbus_register(266,Bmv_ID) / 10
    BatteryWatts     = modbus_register(842,VEsystem_ID)
    BatteryAmps      = modbus_register(261,Bmv_ID) / 10
    BatteryVolts     = modbus_register(259,Bmv_ID) / 100
    BatteryState     = modbus_register(844,VEsystem_ID) # Battery System State 0=idle 1=charging 2=discharging
    ChargeCycles     = modbus_register(284,Bmv_ID)
    BatteryTTG       = modbus_register(846,VEsystem_ID) / .01
    ConsumedAH       = modbus_register(265,Bmv_ID) / -10
    
    if BatteryState == 0:
        BatteryState = "Idle"
    elif BatteryState == 1:
        BatteryState = "Charging"
    elif BatteryState == 2:
        BatteryState = "Discharging"
 
 
    print(f"Battery SOC: {BatterySOC} %")
    print(f"Battery Watts: {BatteryWatts}")
    print(f"Battery Amps: {BatteryAmps}")
    print(f"Battery Volts: {BatteryVolts}")
    print(f"Battery State: {BatteryState}")
    print(f"Battery Charge Cycles: {ChargeCycles}")
    print(f"Battery TTG: {BatteryTTG}")
    print(f"Battery Consimed AH: {ConsumedAH}")
    print(f"=======================================")
    sleep(2)

Here is another handy tool from victron for ModBus

https://github.com/victronenergy/dbus_modbustcp/blob/master/examples/ModbusCli.py

You will still need to

pip install pymodbus

./ModbusCli -d 192.168.20.156 -r 284 -s 223

This will request the #284 register for the BMV amount of charge cycles

and here is the Victron ModBus manual

https://www.victronenergy.com/live/ccgx:modbustcp_faq

and

Here is the most recent version of the register XLS file

https://github.com/victronenergy/dbus_modbustcp/blob/master/CCGX-Modbus-TCP-register-list.xlsx

You also may be able to get an idea about some modbus project you may have from here.

https://github.com/optio50/Victron_Modbus_TCP