As a core drive component of kitchen appliances, the communication protocol selection for range hood electric linear actuators (MALAs) and their control systems must balance reliability, real-time performance, compatibility, and cost-effectiveness. Among the current mainstream communication protocols, Modbus, CAN bus, RS-485, and MQTT are the primary options in this field due to their respective characteristics. The selection should be based on a comprehensive evaluation considering the specific application scenario and technical requirements.
The Modbus protocol, with its advantages of being open-source and free, simple in structure, and highly adaptable, has become the "universal language" for industrial equipment communication. This protocol supports master-slave communication mode, can connect up to 247 slave devices, and is compatible with serial ports and Ethernet, making it suitable for low-cost, multi-node scenarios. For range hood electric linear actuators, if the system only requires basic control functions (such as start/stop and speed adjustment) and the number of devices is small, Modbus RTU (based on RS-485) or Modbus TCP (based on Ethernet) can meet the requirements. Its register system (coil, discrete input, input register, holding register) can clearly map the state and parameters of the range hood electric linear actuator; for example, the speed setpoint can be modified in real time through the holding register, or the current torque data can be read through the input register. However, Modbus's real-time performance is limited by its polling mechanism, which may introduce latency in high-concurrency scenarios with multiple devices.
The CAN bus protocol is renowned for its high reliability and strong anti-interference capabilities, and is widely used in automotive electronics and industrial automation. It employs multi-master contention communication and supports priority arbitration to ensure the priority transmission of critical commands, making it suitable for scenarios with stringent real-time requirements. For example, when a range hood needs to respond quickly to changes in fume concentration, the CAN bus can ensure that the range hood electric linear actuator adjusts the fan speed within milliseconds. Furthermore, the differential signal transmission method of the CAN bus effectively suppresses electromagnetic interference, improving system stability. However, the hardware cost of the CAN bus is relatively high, and it requires a dedicated controller, making it suitable for high-end range hoods or commercial kitchen equipment with stringent performance requirements.
RS-485, as a traditional serial communication standard, is still used by some mid-to-low-end range hoods due to its low cost, long-distance transmission (up to 1200 meters), and ease of use. While its half-duplex communication mode limits data throughput, it is sufficient to meet basic control needs. For example, RS-485 can be used to achieve point-to-point communication between the range hood electric linear actuator and the main control board, transmitting commands such as power on/off and speed adjustment. However, RS-485 lacks a standard protocol specification, requiring a custom application layer protocol, increasing development complexity, and its anti-interference capability is weaker than CAN bus, making it suitable for cost-sensitive home scenarios with minimal environmental interference.
MQTT, as a lightweight IoT communication protocol, has become a popular choice for smart range hoods due to its low power consumption, high flexibility, and support for cloud access. Its publish/subscribe model enables real-time data interaction between the device and the cloud and mobile devices. For example, users can remotely control the range hood electric linear actuator's start/stop or receive device fault warnings via a mobile app. MQTT's QoS levels (0-2) can balance transmission reliability and resource consumption, making it suitable for home scenarios with complex network environments. However, MQTT relies on a network connection; if local control needs to operate offline, it needs to be combined with other protocols (such as Modbus) for redundancy design.
In practical applications, protocol selection requires a trade-off between functional requirements and cost. For example, basic range hoods can use RS-485 or Modbus RTU for low-cost basic control; high-end smart models can use Modbus TCP or MQTT to support remote monitoring and data analysis; commercial kitchen equipment can prioritize CAN bus to ensure high concurrency and high reliability. Furthermore, a hybrid protocol architecture (such as Modbus RTU locally and MQTT in the cloud) can balance local control and remote management, improving system flexibility.
