Modbus can be used to connect a master (eg a PC) and several slaves (eg measuring and control systems). Each bus user must have a unique address. The address 0 is reserved for a broadcast. Each participant is allowed to send messages via the bus. Usually, however, this is initiated by the master and an addressed slave responds. For the correct driver setting, the operating instructions of the terminal must be observed.
COM port: Selection of the communication port.
Baud rate: Specifies the transmission speed.
Stop bits: select the number of stop bits (1 or 2)
Parity: setting parity (without / even / odd)
ASCII mode
In Modbus ASCII, no binary sequence, but ASCII code is transmitted. As a result, it is directly human readable, but data throughput is lower compared to RTU.
RTU mode
Modbus RTU (RTU: Remote Terminal Unit) transmits the data in binary form. This ensures good data throughput, however, the data can not be evaluated directly by humans, but must first be converted into a readable format.