问题

I'm IoT newbie and I have a project with Schneider Power Meter. I read voltage raw data from registers using pymodbus but I don't know how to convert it to the correct value.

Raw data is [24206, 17242] from registers address 3927-3928.

Here is my code :

from pymodbus.client.sync import ModbusSerialClient as ModbusClient

def main():
    try:
        register = int(input("Registers: "))
        modbus = ModbusClient(method='rtu', port='COM4', baudrate=9600, timeout=1, 
            parity='E', bytesize=8
        )
        modbus.connect()
        r = modbus.read_holding_registers(register, 2, unit=1)
        print(r.registers)
        modbus.close()
        return r.registers
    except AttributeError as e:
        print(e)
        return None

if __name__ == "__main__":
    main()

Out:

[24206, 17242]

Registers

Voltage

Raw

Can everyone tell me how to do it?

Thanks.

回答1:

Still, I'm waiting for your code, but with my guess, you will need like the following stuff:

Reading and decoding:

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

def validator(instance):
    if not instance.isError():
        '''.isError() implemented in pymodbus 1.4.0 and above.'''
        decoder = BinaryPayloadDecoder.fromRegisters(
            instance.registers,
            byteorder=Endian.Big, wordorder=Endian.Little
        )   
        return float(decoder.decode_32bit_float())

    else:
        # Error handling.
        print("There aren't the registers, Try again.")
        return None


client = ModbusTcpClient('X.X.X.X', port=502)
connection = client.connect()

if connection:
    request = client.read_holding_registers(3927, count=2, unit=1)
    data = validator(request)
    print(data)

    client.close()

else:
    print('Connection lost, Try again')

[NOTE]:

Your data either is float32 or float32_inverse.