Abstract : DeviceNet fieldbus control of variable frequency speed control systems allows for network-based setting of inverter parameters, fault diagnosis and alarms, and enables motor start/stop, acceleration/deceleration, and direction change. Due to the powerful functions of the ControlLogix system, advanced control algorithms can be used to control motor speed. Keywords : DeviceNet; network control; variable frequency drive; ControlLogix Fieldbus technology is an emerging control technology integrating computer technology, communication technology, integrated circuit technology, and sensing technology. Fieldbus is a fully digital, bidirectional, multi-node communication network connecting field devices to the control room; therefore, it is also called a bidirectional, fully digital communication bus connecting the control room to field devices. The new generation of industrial automatic control systems based on fieldbus technology is a concrete manifestation of the intelligent, digital, and networked development of information technology towards the field. Among various speed control methods for asynchronous motors, the variable voltage variable frequency method has the highest efficiency and best performance. This voltage-frequency coordinated control method can achieve essentially parallel mechanical characteristics during control, exhibiting good speed control performance. With the widespread application of frequency converters in the industrial field, the role of variable frequency speed control technology in energy saving and improving product quality is becoming increasingly apparent. Currently, approximately 60% of frequency converters are used in pumps and fans. The remaining 40% are used in high-tech fields, such as papermaking and metal rolling. Network control of variable frequency speed control systems via fieldbus has practical significance. 1. DeviceNet Fieldbus DeviceNet fieldbus is a flexible, open network suitable for low-level control in industrial environments with high real-time requirements. It is a low-level network that connects field devices (such as sensors and frequency converters) to control room equipment (such as PLCs and computers) without requiring wires to connect them to I/O modules. DeviceNet can connect up to 64 nodes, with a communication rate of up to 500Kb/s, allowing users to connect devices within 500m and the user's programmable controller using a single cable. [b][align=center]For more details, please click: Network Control of Variable Frequency Speed ​​Control Systems Based on DeviceNet Fieldbus[/align][/b]