WSAL24703 – ST3020 Servo/en

Documentation notice: This technical documentation was independently rewritten from an archived supplier source. Check technical details and commands against the product version and manufacturer documentation before use.

Summary

The ST3020 is a dual-axis serial bus servo delivering up to 25 kg·cm of torque at 12 V and featuring a programmable 360° magnetic encoder. It accepts 6–14 V DC input, supports daisy-chaining up to 253 servos over the bus, and provides feedback on position, load, voltage, current, and temperature.

Related products at JW Tech

WSAL24703 – 25kg.cm Wide Range Voltage Serial Bus Servo, High Precision And Large Torque, With Programmable 360 Degrees Magnetic Encoder

Technical overview

Input voltage: 6–14 V DC; can be powered directly from 2S or 3S lithium batteries.
Rotation angle: 360° in servo mode; continuous rotation available in motor mode.
Position sensor resolution: 0.088° (360°/4096).
Locked-rotor torque: 25 kg·cm (≈347.79 oz·in) at 12 V.
Idle speed: 60 RPM (0.167 s per 60°) at 12 V.
Bus ID range: 0–253; factory default ID is 1.
Feedback parameters: position, load, speed, input voltage, current, temperature.
Dimensions: 40.2 mm × 20.2 mm × 40 mm.
Each servo has two interfaces enabling daisy-chain connection of multiple units.
Controlled via an ESP32-based driver board using an Arduino demo; alternatively, an ESP32 flash download tool is provided for the driver board.

Notes and version constraints

The source contains no explicit command lines or API calls; therefore no commands are listed.
When assigning IDs, only one servo should be connected to avoid ID conflicts on the same bus.
Parameter changes require unlocking the EPROM area first; otherwise changes are lost after power loss.
Oversized mounting screws may contact the servo body, causing a sharp current increase that can burn out the servo.
The exact version of the Arduino IDE package (e.g., 2.1.0) and the precise dependency libraries should be verified before compiling.
For custom projects, the source refers to the serial bus servo driver schematic; full circuit details are not reproduced in the source.

Source and revision record

ST3020 Servo - Waveshare Wiki
Source revision: 111163
Captured: 2026-09-05T02:45:14+00:00
SHA-256: 5eb22b9a96ba3a8b687ce34d31522743c4dd87bbd49eb4bf7dca2bc8519c6ded