What is Profibus and how Profibus works ?

Key Information

• Profibus Overview: Profibus stands for Process Field Bus and is an open standard industrial communication protocol, OSI compliant and widely accepted in process automation and material handling.
• Development History: Initiated in 1989 by the German Federal Ministry of Research and Technology in collaboration with automation manufacturers, Profibus is now standardized under the PI Organisation, which also oversees Profinet technology.
• Global Popularity: Profibus is nearly universal in Europe and has significant usage in North America, South America, Africa, and Asia.

Features of Profibus

• Connector and Network Capacity: Utilizes a 9-pin D type connector; supports up to 32 nodes without repeaters and 127 with repeaters.
• Distance and Data Speed: Total network length can reach 24 km with repeaters and optical fiber; data speeds range from 9.6 kbps to 12 Mbps.
• Message Size: Supports messages of up to 256 bytes (244 bytes of data plus 12 bytes overhead).
• Communication Mechanisms: Uses polling and token passing for messaging.

Device Types

• Master Devices: Control the bus and can send messages without a remote request (e.g., PLCs).
• Slave Devices: Typically input devices like sensors and actuators that respond to master requests.

Variants of Profibus

• Profibus DP: Focuses on decentralized peripherals, allowing I/O blocks to be placed in the field, reducing wiring costs.
• Profibus PA: Designed for process automation, it simplifies connections by allowing sensors to connect to a single bus, eliminating the need for I/O blocks in the field.

Electrical Interface

Utilizes Fiber Optic or RS-485 as its electrical interface, with the network topology being a linear bus terminated at both ends. It employs twisted pair cables, usually shielded, and has two cable types depending on transmission speed.

Communication Types

• Token Passing: Used for communication among multiple masters, forming a logical ring.
• Polling: Used for communication between masters and slaves.

Network Configuration

Different configurations can exist, including pure token passing, pure polling, or a hybrid system combining both methods.

Conclusion

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Main Speaker

• The video is presented by an unnamed instructor from Eclectic Classes.