Harmonic Drive LLC | 42 Dunham Ridge, Beverly, MA 01915 | 800-921-3332
Harmonic Drive and Harmonic Planetary are registered trademarks of Harmonic Drive.

RSA-8A Integrated Drive

The RSA mini actuator is extremely compact and delivers high torque with exceptional accuracy and repeatability. This evolutionary product eliminates the need for an external drive and greatly improves wiring while retaining high-positional accuracy and torsional stiffness in a compact housing. This new mini actuator is ideal for use in robotics.

Since it communicates via CANopen, only 4 conductors are needed: CANH, CANL, +24VDC, 0VDC. A single-turn 14bit (16384 cpr) gear output sensing encoder has been integrated along

Key Features:

  • Actuator + Integrated Servo Drive with CANopen® Communication

  • 24VDC Nominal +7 to 30VDC Supply Voltage Range
  • Single Cable with only 4 conductors needed: CANH, CANL, +24VDC, 0VDC
  • Zero Backlash Harmonic Drive® Gearing
  • Flex-rated cable assembly with 4 exit options
  • Input Sensing Encoder: 14 bit resolution (16,384 cpr)
  • Control Modes: Torque, Velocity, Position, CSP, CSV, CST
  • Harmonic Drive® HDL Software


  • Flex-rated extension cables with sealed connectors


Don't see what you need or not sure where to start?

Our team can help you find the right actuator for your application!

Ordering Code RSA-8A Mini with Integrated Servo Drive

RSA - 8 A - 50 - IDT14b - PT1 S - SP
1 2 3 4 5 6 7 8 9

1. Model

RSA Mini Series

2. Size


3. Design Version


4. Gear Ratio

30, 50, 100

5. Encoder Type and Resolution

IDT14b - Integrated Drive
14bit resolution absolute encoder on motor input

6. Output

Blank - Shaft Output
F - Flange Output

7. Cable Exit Options

PT1 - Rear exit cable
PT2 - Right exit cable
PT3 - Left exit cable
PT5 - Front exit cable

8. Special specification

Blank - Standard product
SP____ - Special specification code

RSA Mini actuators with an integrated servo drive offer four cable exit orientation options with standard Lemo® connectors. Optional extension cables are available in 3 lengths.


Specification / Model RSA-8A
Gear Ratio 30 50 100
Maximum Torque N.m 1.8 3.3 4.8
Maximum Speed rpm 283.3 170.0 85.0
Torque Constant
Nm/A(rms) 0.7 1.2 2.0
Maximum Current A(rms) 4.0 4.0 3.5
Allowable continuous current A(rms) 2.05 2 1.7
One-way Positioning Accuracy arc-min 2 2 2
EMF Constant V/(rpm) 0.051 0.085 0.170
Input Power Supply Voltage V 24VDC (+7 to +30VDC)
Phase Resistance Ω(20°C) 0.8
Phase Inductance mH 0.285
Number of Poles 14
Allowable Moment Load Nm 3.46
Moment Stiffness Nm/rad 2.76 x 103
Moment of Inertia
kgm2 7.74x10-4 2.15x10-3 8.60x10-3
Encoder Type and resolution IDT14b - Integrated Drive
14bit resolution absolute encoder on motor input
Output Shaft Resolution*1 Motor counts/rev 491,520 819,200 1,638,400
Enclosure Totally enclosed, self-cooled
Mounting Direction Can be installed in any direction
Mass kg 200 (190 with F option)
Ambient environment specification 0 to 40° C ambient operational temperature range, Storage temperature is -20 to 60° C with humidity 20 to 80%RH (non-condensing). Free from dust, dirt, metallic powder, corrosive gas, flammable gas, oil mist, and others. Avoid outdoor use or direct sunlight. Altitude: 1,000 m or less. Motor insulation: 100 MΩ (500 VDC) or higher. Dielectric strength: 1500 VAC/1 min. Insulation class: B

* Table shows typical output values

*1 Motor ABS encoder resolutions are obtained by (encoder bit count) x (gear ratio)

Outline Dimensions

Shaft Output, Front Exit Cable

Flange Output, Front Exit Cable

Optional Extension Cable: 3 Lengths (ZZ) Available: 3m (03), 5m (05), 10m (10)


HDL-IDE 3.0 Software

HDL-IDE 3.0 software provides the ability to setup or commission the RSA Mini Integrated actuator without connecting to a CANopen master controller. A single actuator can connect to a personal computer or laptop with a CAN communication converter and a power supply. All 256 parameters, including the tuning parameters and 256 general user variables can be set and stored to be recognized by the CANopen master controller operating the specific application. The following are some of the features included in HDL-IDE 3.0 software:

  • Torque Mode and Graph

  • Velocity Mode and Graph

  • Position Mode and Graph

  • Homing Mode

    • Limit Switch

    • Current Position

    • Hardstop Homing

  • Step Response

  • Bode Plot

  • Parameter List

  • Virtual Mode (shown)

for more information.


Contact Us

Submit a Question


Call: 978-532-1800

Hours 8:00am - 5:00pm EST
Monday through Friday