Modbus TCP/IP - IoT - GUI

Installing Dependecies

• Firstly download the program zip file
• Then after install dependecies using this command in bash

pip install -r requirements.txt

• Lastly use this command to run the application

python main.py

Libraries

• GUI library : https://pypi.org/project/PyQt5/
• Database : https://www.sqlite.org/index.html
• Modbus Protocol Library : https://pypi.org/project/pymodbus/
• Azure Communication Library : https://github.com/Azure/azure-sdk-for-python

Azure Communication

• Send data to Azure IoT hub from device : https://docs.microsoft.com/en-us/azure/iot-develop/quickstart-send-telemetry-iot-hub?pivots=programming-language-python
• Send cloud-to-device messages with IoT Hub : https://docs.microsoft.com/en-gb/azure/iot-hub/iot-hub-python-python-c2d

Code Examples

Send cloud-to-device messages with IoT Hub

def message_handler(message):

  a = str(message)

  list = a.split(",")

  newlist = []

  for i in list:

      newlist.append(int(re.search(r'\d+', i).group()))
  
  print(newlist)

  client = ModbusClient(host="192.168.1.200", port = 502)

  client.open()

  client.write_multiple_registers(newlist[0], [newlist[1]])

def getDatafromAzure():
  print ("Starting the Python IoT Hub C2D Messaging device sample...")

  # Instantiate the client
  clientAzure = IoTHubDeviceClient.create_from_connection_string(CONNECTION_STRING)

  print ("Waiting for C2D messages, press Ctrl-C to exit")
  try:
      # Attach the handler to the client
      clientAzure.on_message_received = message_handler

      while True:
          time.sleep(1000)
  except KeyboardInterrupt:
      print("IoT Hub C2D Messaging device sample stopped")
  finally:
      # Graceful exit
      print("Shutting down IoT Hub Client")
      clientAzure.shutdown()

Send data to Azure IoT hub from device

# 1- First thing you have to do is go Azure portal and open bash command line then write az iot hub monitor-events --hub-name modbus-tcp-iot --device-id mypi
# 2- this command starts monitoring for your device

def sendDatatoAzure(registerNumber, distance):

   clientAzure = IoTHubDeviceClient.create_from_connection_string(CONNECTION_STRING)

   client = ModbusClient(host="192.168.1.200", port = 502)

   client.open()

   data = client.read_holding_registers(registerNumber, distance)

   message = Message(data)

   clientAzure.send_message(str(message))
   
if __name__ == '__main__':

   sendDatatoAzure()
   #getDatafromAzure()

Work Principle

-You can just enter the ip address of the connected slave device and start reading the register values.