Master-Slave is a communication architecture used in digital electronics and control systems. In this model, one device (designated as the "Master") manages the operation and communication flow of one or more connected devices (the "Slaves").
Operational Principles
This hierarchical model ensures an orderly exchange of data on a communication bus.
- Master Initiates: The Master device starts all communication transactions. It sends commands or requests data.
- Slave Responds: Slave devices listen for commands addressed to them. They do not initiate communication and only transmit data when requested by the Master.
- Addressing: In systems with multiple Slaves, the Master identifies each device using a unique address or ID.
Typical Applications
Master-Slave architectures are ideal for industrial automation and system integration.
- Common Protocols: I2C, SPI, and Modbus commonly utilize this structure.
- System Example: In an RS-485 multi-drop system, a central host computer (Master) controls multiple DC power supplies or high-voltage modules (Slaves). This allows for synchronized operation and centralized monitoring.
Industry Note on Terminology
Due to historical connotations, the technology industry is adopting alternative terms to describe this architecture. Common replacements include Controller/Device, Primary/Secondary, or Leader/Follower. These terms describe the same technical relationship and are increasingly found in modern specifications.