The debugging of Modbus communication can be done using serial port debugging tools or with the help of commonly used Modbus debugging tools such as ModScan, Modbus Poll and Modbus Slave. ModScan and Modbus Poll can simulate Modbus RTU Client or Modbus TCP Client, while Modbus Slave can simulate Modbus RTU Server or Modbus TCP Server. All the three tools are third-party software and can be purchased on their websites or downloaded for trial.