What is the difference between MPI and PROFIBUS-DP? -Solutions - Huaqiang Electronic Network

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Both MPI and DP are based on the RS485 interface, making them suitable for industrial communication. However, they differ in their application scenarios and network configurations.

MPI (Multipoint Interface) is a multi-point communication protocol used primarily in Siemens S7 systems. It’s ideal for short-range communication between a central host and a limited number of PLCs. The communication speed ranges from 19.2 Kbit/s to 12 Mbit/s, and the network can support up to 32 stations. In one segment, the maximum distance is 50 meters at a baud rate of 187.5 Kbit/s, but this can be extended using an RS485 repeater. MPI supports both master-master and master-slave communication, which makes it flexible for small-scale automation setups.

PROFIBUS-DP, on the other hand, is more advanced and scalable. It allows for single or multi-master configurations, with the ability to connect up to 126 devices on a single bus. The system configuration includes details such as the number of stations, station addresses, input/output addresses, data formats, diagnostic information, and bus parameters. There are three main types of equipment in a PROFIBUS-DP system:

• DPM1 (Primary DP Master): This is the central controller responsible for managing communication with distributed stations (DP slaves) within a set time frame. A typical DPM1 could be a PLC or a PC.
• DPM2 (Secondary DP Master): This device is used during system configuration and operation, such as a programmer, configuration tool, or HMI, for monitoring and control purposes.
• DP Slave: These are peripheral devices like I/O modules, drives, HMIs, or valves that handle input and output operations.

In a single-master system, only one master is active during operation, ensuring clear and controlled communication on the bus. This structure helps avoid conflicts and improves reliability in complex environments.