Answer / alok

Modbus is communication protocol (set of rules for proper communication) developed by modicon, now it is an open protocol (every company can use it without paying royalty). In modbus we can transmit signal upto 1200 m at 125 kbps.It is used for Master- Slave application and maximum 32 devices can be connected for multi drop application without repeaters. It has many variants Modbus RTU and Modbus ASCII for serial communication it can use RS232 or RS485 protocol (depends upon distance, application type point to point or multi drop,noise immunity) and Modbus TCP/IP and Modbus Plus for ethernet protocol


Profibus is also communication protocol developed by siemens and it is proprietary (only used by developer) of siemens. we cn transmit signal upto 2 to 5 km at 12 mbps and we can connect upto 127 devices without repeaters. It also has many variants such as Profibus PA, Profibus DP, ProfiNet, ProfiSafe (used dependind upon the application)

Answer / nirav

Modbus - for connecting differnent make plc data to dcs.

Profibus - same make.

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