DFRobot
ST3215 Serial Bus Servo 19.5kg.cm 7.4V 360° Encoder
· MPN: SER0069
Built for demanding multi-axis robots, this smart serial bus servo combines high torque, absolute position feedback and simplified wiring over a TTL serial b...
Built for demanding multi-axis robots, this smart serial bus servo combines high torque, absolute position feedback and simplified wiring over a TTL serial bus. It is suited to projects such as robotic arms, educational robots, quadrupeds, humanoid robots and small-scale sorting systems.
The servo uses a 12-bit magnetic encoder for true 360° absolute position sensing, with 4096 steps and 0.088° per step resolution. It also supports ±7-turn multi-turn absolute positioning for movements beyond a single rotation.
Control is via half-duplex UART, allowing up to 253 servos to be daisy-chained from a single host I/O port. Each servo can be assigned its own ID, reducing cable clutter in complex robotic builds.
The package includes one ST3215 Serial Bus Servo, a servo horn screw accessory kit and a 3-pin servo cable.
Features:
- Serial bus control: TTL serial bus interface for controlling up to 253 servos from a single port
- Magnetic encoder: 12-bit high-precision magnetic encoder for 360° absolute positioning
- High resolution: 4096 steps with 0.088° per step
- Multi-turn positioning: ±7 turns absolute positioning
- High torque: 19.5kg·cm stall torque at 7.4V
- Gear train: 1:345 gear train made from copper and aluminium
- Housing: High-strength PA+GF housing
- Operating modes: Angle Servo Mode, Speed Closed-loop Mode, Speed Open-loop Mode and Stepping Mode
- Feedback: Real-time feedback on position, speed, load, input voltage, current and internal temperature
- Protection: Built-in protection against over-stall, over-current, over-voltage and over-heating
Specifications:
- Operating voltage: 4-7.4V
- No-load speed: 0.238s/60° (42RPM)@6V；0.192s/60° (52RPM)@7.4V
- No-load current: 130mA@6V；150mA@7.4V
- Stall torque: 16.5kg.cm@6V；19.5kg.cm@7.4V
- Stall current: 2A@6V；2.5A@7.4V
- Standby current: 6mA
- Rated load: 4kg.cm@6V；5kg.cm@7.4V
- Rated current: 500mA@6V；650mA@7.4V
- Motor resistance: 2.5Ω
- Torque constant (Kt): 8kg.cm/A
- Dimensions: 45.2×24.7×35mm
- Housing: PA+GF
- Gear material: Copper
- Bearing: Ball bearing
- Sensor: 12-bit magnetic encoder
- Rotation: 360°
- Connector: 3-pin (Black-GND, Red-VCC, Blue-Signal/TTL)
- Cable length: 15cm
- Weight: 55±1g
- Output shaft: 25T/OD5.9mm
- Gear ratio: 1:345
- Gear backlash: ≤0.5°
- Output shaft screw: M3×6
- Motor type: Coreless
- Signal: Digital
- Protocol: Half-duplex UART (8-bit, 1 stop bit, no parity)
- ID range: 0-253
- Baud rate: 38.4kbps-1Mbps (default: 1Mbps)
- Control algorithm: PID
- Midpoint: 180° (2048 steps)
- Resolution: 0.088°
- Rotation direction: Clockwise (0→4096)
- Feedback: Load, position, operating speed, input voltage, operating current, operating temperature
- Overload: Triggers when stalled torque exceeds 80% of stall value for 2s; cleared by sending new position command. Customizable torque threshold/duration.
- Overcurrent: Disables output when current >2A for 2s; cleared by sending new position command. Customizable current threshold/duration.
- Overvoltage: Activates when voltage >7.4V or <4V; auto-recovery within normal range. Customizable voltage range.
- Overheat: Disables torque output when temperature >70°C.
- Mode 0: Angle Servo (default; 0-360° absolute positioning)
- Mode 1: Speed Closed-loop Motor (maintains speed under load)
- Mode 2: Speed Open-loop Motor (speed drops under load)
- Mode 3: Stepping Mode (incremental motion from current position)
- Multi-Turn Mode: ±7-turn absolute positioning at maximum precision (turn count not saved after power loss).
- Center Calibration: One-click midpoint setting at any 360° position.
- Load lifespan: >100,000 cycles
- Motor noise: 45±5dB
- Servo noise: 60±5dB
- Storage temp: -30°C to +80°C
- Operating temp: -20°C to +60°C
- Max update rate: 1ms
- High-level voltage: 2-5V
- Low-level voltage: 0-0.45V
A strong fit for robotics builds that need compact wiring, position feedback and programmable motion modes over a UART bus.
Jargon buster
Plain-language definitions for the technical terms used above.
- baud
- Baud is the signalling rate of a serial connection, often used as the speed setting for UART communication. Matching the baud rate matters because both connected devices must use the same setting for readable data.
- encoder
- A device attached to a motor or shaft that reports movement, such as rotation steps or position. In a pump system, an encoder can help measure or control how much the motor has turned, which affects how repeatable the watering amount can be.
- servo
- A servo is a motor with built-in position control, usually told to move to a specific angle by a control signal. It matters when you need repeatable movement, such as steering, arms, flaps, or linkages, rather than continuous spinning.
- Stall torque
- The maximum twisting force a servo can produce when its output is held still and cannot move. It helps you judge whether the servo is strong enough for a robot joint, steering linkage, or other load.
- Torque
- A twisting force that causes something to rotate, usually measured in newton-metres or kilogram-centimetres. It matters when choosing motors, servos, gears, and tools because higher torque is needed to lift heavier loads, turn larger wheels, or move mechanisms without stalling.
- TTL serial
- A simple serial data connection that uses microcontroller logic-level signals rather than computer RS-232 voltage levels. It matters because the camera can connect directly to many microcontroller pins or a USB-to-TTL serial adapter, but not safely to an old-style RS-232 port without conversion.
- UART
- UART is a simple serial connection that sends data over separate transmit and receive wires, often labelled TX and RX. It matters because this module is designed to replace a wired UART cable with a wireless link while keeping the same serial data format.
Find this product in
Robotics & Motion
Supplier page — dfrobot.com
Supplier Description · 136.3 KB · Click any page to view full size
