– RS485: It is a physical layer electrical standard that specifies the electrical characteristics of data transmission, signal levels, transmission distances, and connection methods. It uses differential signaling for transmission, has strong anti-interference capabilities, and can achieve half-duplex communication between multiple devices. It is commonly used for long-distance data transmission in industrial environments.
– Modbus: It is an application layer communication protocol that defines the format of data frames, command types, rules for data transmission, and how devices exchange information. It specifies the semantics and syntax of communication between devices, enabling interoperability among devices from different manufacturers.
Application Scenarios
– RS485: It can be used in any scenario requiring long-distance, anti-interference serial data transmission, such as in industrial automation control systems, security monitoring systems, and smart buildings, connecting various sensors, actuators, controllers, and other devices.
– Modbus: It is primarily used in the field of industrial automation to facilitate communication and data exchange between devices such as PLCs, smart instruments, and frequency converters produced by different manufacturers, enabling system integration and collaborative operation.
Relationship
RS485 is one of the commonly used physical layer transmission methods for the Modbus protocol. The Modbus protocol can transmit data based on the RS485 electrical standard. However, Modbus can also operate over other physical layers, such as RS232 and Ethernet. RS485 merely provides a physical channel for data transmission and does not concern itself with the content and protocol of the transmitted data; it can carry other communication protocols in addition to Modbus.