PROSAGA码农传奇-MQTT/MODBUS-Pymodbus：Modbus RTU使用reactor

<div class =“post-text”itemprop =“text”>
  
    以下解决方案适合我。我的设备配置如下：
  
  <BLOCKQUOTE>
    
      的
        设备配置：
      </强>
       
      
  波特率= 9600，奇偶校验='E'，字节大小= 8超时= 0.2
       
      
  协议：RTU
       
      
  PLC使用串口转USB连接到RaspberryPI。
       
    
  </BLOCKQUOTE>
  
    的
      工作守则：
    </强>
  
   <pre>
 <code>
 import logging
from threading import Thread
from time import sleep

from pymodbus.client.async.twisted import ModbusClientProtocol
from pymodbus.constants import Endian
from pymodbus.factory import ClientDecoder
from pymodbus.payload import BinaryPayloadDecoder
from pymodbus.transaction import ModbusRtuFramer
from serial import EIGHTBITS
from serial import PARITY_EVEN
from serial import STOPBITS_ONE
from twisted.internet import protocol
from twisted.internet import serialport, reactor

FORMAT = ('%(asctime)-15s %(threadName)-15s '
      '%(levelname)-8s %(module)-15s:%(lineno)-8s %(message)s')
logging.basicConfig(format=FORMAT)
logger = logging.getLogger()
logger.setLevel(logging.INFO)

def readDevices(modbusRTUDevice):
    deviceIP = modbusRTUDevice["ip"]
    devicePort = modbusRTUDevice["port"]
    logger.info("Connecting to Modbus RTU device at address {0}".format(deviceIP +    ":" + str(devicePort)))
    modbusClientFactory = CustomModbusClientFactory()
    modbusClientFactory.address = deviceIP
    modbusClientFactory.modbusDevice = modbusRTUDevice
    SerialModbusClient(modbusClientFactory, devicePort, reactor, baudrate=9600, bytesize=EIGHTBITS,
                   parity=PARITY_EVEN, stopbits=STOPBITS_ONE, timeout=0.2, xonxoff=0, rtscts=0)
    Thread(target=reactor.run, args=(False,)).start()  # @UndefinedVariable

class SerialModbusClient(serialport.SerialPort):

def __init__(self, factory, *args, **kwargs):
        serialport.SerialPort.__init__(self, factory.buildProtocol(), *args, **kwargs)

class CustomModbusClientFactory(protocol.ClientFactory):
    modbusDevice = {}

def buildProtocol(self, addr=None):
        modbusClientProtocol = CustomModbusClientProtocol()
        modbusClientProtocol.factory = self
        modbusClientProtocol.modbusDevice = self.modbusDevice
        return modbusClientProtocol

def clientConnectionLost(self, connector, reason):
        modbusTcpDeviceIP = self.modbusDevice["ip"]
        modbusTcpDevicePort = self.modbusDevice["port"]
        logger.critical("Connection lost with device running on {0}:{1}.".format(modbusTcpDeviceIP, modbusTcpDevicePort))
        logger.critical("Root Cause : {0}".format(reason))
        connector.connect()

def clientConnectionFailed(self, connector, reason):
        modbusTcpDeviceIP = self.modbusDevice["ip"]
        modbusTcpDevicePort = self.modbusDevice["port"]
        logger.critical("Connection failed with device running on {0}:{1}.".format(modbusTcpDeviceIP, modbusTcpDevicePort))
        logger.critical("Root Cause : {0}".format(reason))
        connector.connect()

class CustomModbusClientProtocol(ModbusClientProtocol):

def connectionMade(self):
        framer = ModbusRtuFramer(ClientDecoder(), client=None)
        ModbusClientProtocol.__init__(self, framer)
        ModbusClientProtocol.connectionMade(self)
        deviceIP = self.modbusDevice["ip"]
        devicePort = self.modbusDevice["port"]
        logger.info("Modbus RTU device connected at address logger{0}".format(deviceIP + ":" + str(devicePort)))
        reactor.callLater(5, self.read)  # @UndefinedVariable

def read(self):
        deviceIP = self.modbusDevice["ip"]
        devicePort = self.modbusDevice["port"]
        slaveAddress = self.modbusDevice["slaveAddress"]
        logger.info("Reading holding registers of Modbus RTU device at address {0}...".format(deviceIP + ":" + str(devicePort)))
        deferred = self.read_holding_registers(0, 1, unit=slaveAddress)
        deferred.addCallbacks(self.requestFetched, self.requestNotFetched)

def requestNotFetched(self, error):
        logger.info("Error reading registers of Modbus RTU device : {0}".format(error))
        sleep(0.5)

def requestFetched(self, response):
        logger.info("Inside request fetched...")
        decoder = BinaryPayloadDecoder.fromRegisters(response.registers, byteorder=Endian.Big, wordorder=Endian.Big)
        skipBytesCount = 0
        decoder.skip_bytes(skipBytesCount)
        registerValue = decoder.decode_16bit_int()
        skipBytesCount += 2
        logger.info("Sensor updated to value '{0}'.".format(registerValue))
        reactor.callLater(5, self.read)  # @UndefinedVariable

readDevices({"ip": "127.0.0.1", "port": "/dev/ttyUSB0", "slaveAddress": 1})

</code>
 </pre>
  
    的
      输出：
    </强>
  
   <pre>
 <code>
 2019-02-03 00:39:00,623 MainThread INFO TestRTU:26 Connecting to Modbus RTU device at address 127.0.0.1:/dev/ttyUSB0
2019-02-03 00:39:00,628 MainThread INFO TestRTU:73 Modbus RTU device connected at address logger127.0.0.1:/dev/ttyUSB0
2019-02-03 00:39:05,634 Thread-1 INFO TestRTU:80 Reading holding registers of Modbus RTU device at address 127.0.0.1:/dev/ttyUSB0...
2019-02-03 00:39:05,676 Thread-1 INFO TestRTU:89 Inside request fetched...
2019-02-03 00:39:05,677 Thread-1 INFO TestRTU:95 Sensor updated to value '26'.

</code>
 </pre>
  <BLOCKQUOTE>
    
      <a href="https://github.com/Almad/twisted/blob/master/twisted/internet/_posixserialport.py" rel="nofollow noreferrer">
        serialport.SerialPort。
        的
          在里面
        </强>
        （......）
      </A>
       构造函数负责初始化与设备进行串行通信所需的所有参数。您只需在此更新设备设置＆amp;运行代码。
  
       <code>
 SerialModbusClient(modbusClientFactory, devicePort, reactor, baudrate=9600, bytesize=EIGHTBITS, parity=PARITY_EVEN, stopbits=STOPBITS_ONE, timeout=0.2, xonxoff=0, rtscts=0)
 </code>
    
  </BLOCKQUOTE>
</DIV>

Pymodbus：Modbus RTU使用reactor - 回调永远不会被调用