How to connect modbus?

MODBUS is an industrial communication protocol, generally used for PLC, instrumentation and other equipment for data exchange, or host group configuration and equipment data communication. Since the communication, the first need to establish a communication channel, such as 485 or 232 serial port connection, Ethernet connection, etc., and then determine the communication between the two sides of the host which do slave, the host takes the initiative to the slave request channel connection, after the connection is complete, you can through the MODBUS commands and datagrams for data communication.