我已经尝试了这个平台上存在的与pymodpoll相关的许多修复。我能够成功写入寄存器，但无法读取，我已确认我尝试读取的寄存器实际上是RW寄存器。Datasheet的产品。
用于阅读寄存器的mod poll命令是modpoll -m rtu -0 -1 -a 1 -b 9600 -p none -r 48 /dev/ttyUSB0

from pymodbus.client import ModbusSerialClient as modbus
    #Connection to the modbus
    def connect(self) -> None:
        self.modbus = modbus(method='rtu', 
                            port="/dev/ttyUSB0", 
                            baudrate=9600,
                            stopbits=1,
                            bytesize=8,
                            timeout=1)
        self.modbus.connect()

    #function that works properly for setting the register value
    def set_voltage(self, voltage:float =0) -> None:
        if (voltage < self.min_volt) or (voltage > self.max_volt):
            raise modbusError(
                "Invalid voltage provided to the interface, voltage provided: {0}"
                .format(voltage))
        self.modbus.write_register(0x0030, int(voltage*100), unit=1)

    #Read register function
    def get_voltage_target(self) -> float:
        reg =  self.modbus.read_holding_registers(0x0030, 1, unit=1)
        print(reg.registers)

输出：

AttributeError: 'ModbusIOException' object has no attribute 'registers'

我收到这个错误从reg.registers打印，我假设这只是从事实，我没有正确连接到modbus读取正确的寄存器。
这是我目前正在使用的代码，感谢您的帮助！

简化版编辑：

from pymodbus.client import ModbusSerialClient as RTUClient
import logging
logging.basicConfig()
log = logging.getLogger()
log.setLevel(logging.DEBUG)

PowerSupplyMB = RTUClient(method='rtu', port="/dev/ttyUSB0", baudrate=9600,stopbits=1,bytesize=8,timeout=1)
PowerSupplyMB.connect()
PowerSupplyMB.write_register(0x0030, int(10.2*100), unit=1)
mb_response  = PowerSupplyMB.read_holding_registers(0x0030, 1, unit=1)

if not mb_response.isError():
    '''isError() method implemented in pymodbus 1.4.0 and above'''
    print(mb_response.registers)  # Your problem is here.

else:
    # Do stuff for error handling.
    print('Error message: {}'.format(mb_response))

输出：

DEBUG:pymodbus.logging:Current transaction state - IDLE
DEBUG:pymodbus.logging:Running transaction 1
DEBUG:pymodbus.logging:SEND: 0x0 0x3 0x0 0x30 0x0 0x1 0x85 0xd4
DEBUG:pymodbus.logging:New Transaction state "SENDING"
DEBUG:pymodbus.logging:Changing transaction state from "SENDING" to "WAITING FOR REPLY"
DEBUG:pymodbus.logging:Transaction failed. (Modbus Error: [Invalid Message] No response received, expected at least 4 bytes (0 received))
DEBUG:pymodbus.logging:Frame - [b''] not ready
DEBUG:pymodbus.logging:Getting transaction 0
DEBUG:pymodbus.logging:Changing transaction state from "PROCESSING REPLY" to "TRANSACTION_COMPLETE"
Error message: Modbus Error: [Input/Output] Modbus Error: [Invalid Message] No response received, expected at least 4 bytes (0 received)

进一步的调查表明，registers包含错误-Modbus Error: [Input/Output] No Response received from the remote slave/Unable to decode response。