ST3215 Serial Bus Servo (19.5kg, 7.4V, 360 Magnetic Encoder

The ST3215 is an intelligent, high-performance serial bus servo designed for advanced robotics and automation. It operates on a TTL serial bus interface, enabling control of up to 253 servos from a single port, which drastically simplifies wiring in complex multi-axis systems. The core of the ST3215 is a 12-bit high-precision magnetic encoder, offering 360° absolute positioning with exceptional accuracy (0.088°) that far exceeds traditional potentiometers. Key features include a powerful 19.5kg·cm stall torque, four distinct operating modes, and real-time feedback of critical parameters such as position, load, and temperature. This combination of strength, precision, and intelligence makes it an ideal actuator for demanding applications like robotic arms, quadruped robots, and humanoid robots.

High Torque & Durable Metal Gear Train

Engineered for strength and longevity, the ST3215 serial bus servo delivers a substantial stall torque of 19.5kg·cm at 7.4V. Its dual-axis, low-profile internal structure houses a robust 1:345 gear train made from a combination of copper and aluminum, ensuring efficient power transmission and high load capacity while maintaining low operational noise. The entire assembly is protected by a high-strength PA+GF housing, making it resilient enough for continuous use in dynamic robotic applications.

High-Precision 360° Magnetic Encoder

At the heart of its positioning system is a 12-bit magnetic encoder. Unlike conventional potentiometers, it can provide true 360° absolute position sensing without wear, achieving a high resolution of 4096 steps (0.088° per step). This allows for exceptionally smooth and precise motion control. The serial bus servo also supports multi-turn absolute positioning (±7 turns), enabling complex movements beyond a single rotation.

Intelligent Serial Bus Control

The ST3215 serial bus servo utilizes a half-duplex UART communication protocol, allowing up to 253 servos to be daisy-chained together and controlled via a single host I/O port. Each servo is assigned a unique ID (0-253), enabling individual command execution and data polling. This bus architecture significantly reduces cable clutter and simplifies the electronic design of sophisticated multi-degree-of-freedom (DOF) systems.

Four Versatile Operating Modes

To accommodate a wide range of applications, the serial bus servo features four programmable modes. The default Angle Servo Mode provides standard 0-360° absolute positioning with acceleration control for smooth motion. For continuous rotation, Speed Closed-loop Mode maintains a constant speed under varying loads, while Speed Open-loop Mode behaves like a standard DC motor. Finally, Stepping Mode allows for precise, incremental movements relative to the current position.

Real-Time Feedback & Comprehensive Protection

This smart servo offers closed-loop control by providing real-time feedback on position, speed, load, input voltage, current, and internal temperature. This data is critical for monitoring system health and creating adaptive behaviors. Furthermore, built-in protection mechanisms guard against over-stall, over-current, over-voltage, and over-heating, automatically disabling torque output to prevent damage and ensuring system reliability.

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