19" Rack-Mounted Brushless DC Controller

  • 19", 1U Rack-Mounted Enclosure
  • Supports 3-Phase, Brushless DC Servo Motors
    with up to 2.5 A Peak Coil Current
  • Accepts Optical Encoder Feedback
  • APT™ Control Software Suite

GUI Panel


1-Channel Controller

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RBD201 Front and Rear Panels

RBD201 Rack Mounted
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The image above shows an RBD201 controller mounted in a typical 19" rack system.


  • Supports Thorlabs' Range of 3-Phase, Brushless DC Servo Motor Products
  • Encoder Feedback for Closed-Loop Velocity and Position Control
  • USER I/O Port Exposes Encoder Signals for Monitoring
  • AUX I/O Port Exposes Digital Input and Output Signals
  • Fully Supported by the APT™ Software Control Suite
  • Seamless Integration with All APT™ Family Controllers
  • ActiveX® Software Graphical Panels

The RBD201 Brushless DC Motor Controller is ideal for motion control applications demanding high-speed (hundreds of mm/s) and high-encoder-resolution (<100 nm) operation. This 1U-high, single-channel controller is designed to fit in a standard 19" rack. It offers high-precision motion control in a wide range of applications, especially when used with our DDS220 or DDS600 linear motor translation stages, where speeds of up to 400 mm/s can be achieved. With the latest digital and analog techniques and high-bandwidth, high-power servo control circuitry, these controllers have been designed to drive Thorlabs' range of 3-phase, brushless DC servo motor products with peak coil currents up to 2.5 A.

Integrated into the APT™ family of products, the RBD201 controller offers Thorlabs' standard control and programming interface, allowing for easy integration into automated motion control applications. The unit is capable of being reprogrammed in-field, allowing the option to upgrade with future firmware releases as soon as new programming interfaces (such as microscopy standard command sets) are added.

USB connectivity provides easy plug-and-play PC operation. Multiple units can be connected to a single PC via standard USB hub technology for multi-axis motion control applications (such as our MLS203 series of dual-axis stages). Coupling this with the user friendly APT™ software allows the user to get reasonably complex move sequences up and running in a short space of time. For example, all relevant operating parameters are set automatically for Thorlabs' stage and actuator products. Advanced custom motion control applications and sequences are also possible using the extensive ActiveX® programming environment described in more detail on the Motion Control Software tab.

We have ensured that the software interfaces to the RBD201 controller is highly integrated with all other APT™ family controllers, providing easy system integration and reduced learning curve. As one of the newest members of the APT™ family of controllers, this unit is backed up by the full-featured APT™ suite of PC software tools for immediate, easy out-of-the-box configuration and usage.

Note: The RBD201 controller is specifically designed for use in a 19" rack. For benchtop applications, please see our benchtop controllers.

Cables for connecting actuators or stages to the controller are shipped with the actuators or stages, not the controller. If you need help identifying the appropriate replacement cable, please contact Tech Support.

Not For Use with Brushed DC Motors or the DDS050 and DDS100 Linear Stages
This controller is designed for use with high power, brushless DC servo motors. For control of the Thorlabs' brushed DC servo motor devices, please see the KDC101 Brushed DC Servo Motor Driver K-Cube™. For controlling the DDS050 and DDS100 Linear Stages, please see the KBD101 Brushless DC Servo Motor Driver K-Cube.

Optional Joysticks
The MJC2 and MJC3 joysticks have been designed to provide intuitive, tactile, manual positioning of the stage being controlled. The joysticks feature a two-axis joystick knob for XY control or a three-axis joystick knob for XYZ control, respectively. In most applications, the default parameter settings saved within the controller allow the joystick to be used out of the box, with no need for further setup, thereby negating the requirement to be connected to a host PC, and allowing true remote operation.

Other Controllers
Thorlabs also manufactures a complete range of motion controllers for DC servo motors, stepper motors, and piezoelectric actuators. Please see the links below for more information.

Number of Channels1
Motor Drive Connector8 Pin DIN, Round, Female
Feedback Connector15-Pin D-Type
Brushless Continuous Current Output2.5 A
PWM Frequency40 kHz
Operating ModesPosition and Velocity
Control Algorithm16-Bit Digital PID Servo Loop with Velocity and Acceleration Feedforward
Velocity ProfileTrapezoidal/S-Curve
Position Count32 Bit
Position FeedbackIncremental Encoder
Encoder Bandwidth2.5 MHz (10 M Counts/sec)
Encoder Supply5 V
AUX Control Connector15-Pin D-Type
Input Power Requirements
(Region-Specific Power Cord Included)
150 VA
Voltage: 100 to 240 VAC
Frequency: 50 to 60 Hz
Fuse: 2.0 A
Dimensions482.6 x 264.8 x 43.7 mm (19" x 10.43" x 1.72")
Weight3.4 kg (7.5 lbs)




1Motor Phase V5Stage ID
3Temp Sensor (Not Used)7Motor Phase W
4Motor Phase U8Enable


D-type Female


1Not Connected9GND
2GND10Limit Switch +
3Not Connected11Limit Switch -
4Index -12Index +
5QB -13QB +
6QA -14QA +
7a5 V15Not Connected
8a5 V
  • Pins 7 and 8 are Short-Circuited Internally


D-Type Male

15 Oin DIN Male

15 V9QA +
2Trigger IN10QA -
3Trigger OUT11QB+
4Ground12QB -
5Ground13Index/Ref +
6For Future Use14Index/Ref -
7For Future Use15Ground
8For Future Use


D-Type Female


1Digital O/P 19Digital Ground
2Digital O/P 210Digital Ground
3Digital O/P 311For Future Use
4Digital O/P 412For Future Use
5Digital Ground13Digital I/P 4
6Digital I/P 1145 V Supply O/P
7Digital I/P 2155 V Supply O/P
8Digital I/P 3


Mini DIN Female

Handset Connector

1RX (Controller Input)/RS2324Supply Voltage for Handset 5V
2Ground5TX (Controller Output)/RS232


D-Type Male

9Pin DIN Male

1Not Connected6Not Connected
2RX (Controller Input)7Not Connected
3TX (Controller Output)8Not Connected
4Not Connected9Not Connected

Driver Flexibility

A wide range of brushless DC servo motors and associated actuators are available, each with their own operational specifications. For this reason, the apt™ DC Servo controllers are fully configurable (parameterized) to support different motor/actuator combinations. Key settings such as PID control loop values, min and max stage position, leadscrew pitch, and limit switch configuration are exposed through the supplied apt™ software. Moreover, relative and absolute motion can be initiated with move profiles set using velocity profile parameters. Homing sequences for establishing a zero datum are also fully configurable for a particular stage or actuator. For simplicity of operation, the apt™ software incorporates pre-configured settings for each Thorlabs' stage and actuator including the MLS203 stage.

All key parameters can be adjusted through direct interaction with the graphical software panels supplied. However, for custom motion control applications, all controller settings and commands are also accessible through the ActiveX® programming libraries. These programming libraries are very comprehensive, providing hundreds of functions and parameters that can be accessed from user-written programs.

They are language independent in nature and consequently are supported by a large variety of programming environments that are ActiveX ® compliant. These include LabVIEW, Visual Basic, C++, Matlab, and HPVEE.

Note that all such settings and parameters are also accessible through the ActiveX® programmable interfaces for automated alignment sequences. Refer to the Motion Control Software tab for further information on the apt™ software support for the RBD201.

Full Software GUI Conrol Suite & ActiveX® Controls Included

MMR601 ODC001

A full and sophisticated software support suite is supplied with the BBD controllers. The suite includes a number of user utilities to allow immediate operation of the unit without any detailed pre-configuration. All operating modes can be accessed manually and all operating parameters can be changed and saved for next time use. For more advanced 'custom' motion control applications, a fully featured ActiveX® programming environment is also included to facilitate custom application development in a wide range of programming environments. Note that all such settings and parameters described above are also accessible through these ActiveX® programmable interfaces. For further information on the apt™ software support for the RBD201 refer to the Motion Control Software tab. Demonstration videos illustrating how to program the apt™ software are also available for viewing from the APT Tutorials tab.

The ActiveX® apt™ system software shipped with these units is also compatible with other apt™ family controllers including our multi-channel rack-based system and smaller optical table mountable T-Cube™ Controllers. This single unified software offering allows seamless mixing of any apt™ benchtop, table top and rack based units in any single positioning application.

The key innovation of the apt™ range of controllers and associated mechanical products is the ease and speed with which complete automated alignment/positioning systems can be engineered at both the hardware and software level. All controllers in the apt™ range are equipped with USB connectivity. The multi-drop USB bus allows multiple apt™ units to be connected to a single controller PC using commerical USB hubs and cables. When planning a multi-channel application, simply add up the number and type of drive channels required and connect together the associated number of APT controllers.

Software Developers Support CD

A developers’ kit is shipped with all of our apt™ series controllers. This additional software support is intended for use by software developers working on large, system integration projects that incorporate apt™ products. The kit contains an extensive selection of useful code samples as well as a library of Video Tutorials.

Thorlabs offers two platforms to drive our wide range of motion controllers: our Kinesis® software package or the legacy APT™ (Advanced Positioning Technology) software package. Either package can be used to control devices in the Kinesis family, which covers a wide range of motion controllers ranging from small, low-powered, single-channel drivers (such as the K-Cubes™ and T-Cubes™) to high-power, multi-channel, modular 19" rack nanopositioning systems (the APT Rack System).

The Kinesis Software features .NET controls which can be used by 3rd party developers working in the latest C#, Visual Basic, LabVIEW™, or any .NET compatible languages to create custom applications. Low-level DLL libraries are included for applications not expected to use the .NET framework. A Central Sequence Manager supports integration and synchronization of all Thorlabs motion control hardware.

Kinesis Software
Kinesis GUI Screen
APT Software
APT GUI Screen

Our legacy APT System Software platform offers ActiveX-based controls which can be used by 3rd party developers working on C#, Visual Basic, LabVIEW™, or any Active-X compatible languages to create custom applications and includes a simulator mode to assist in developing custom applications without requiring hardware.

By providing these common software platforms, Thorlabs has ensured that users can easily mix and match any of the Kinesis and APT controllers in a single application, while only having to learn a single set of software tools. In this way, it is perfectly feasible to combine any of the controllers from single-axis to multi-axis systems and control all from a single, PC-based unified software interface.

The software packages allow two methods of usage: graphical user interface (GUI) utilities for direct interaction with and control of the controllers 'out of the box', and a set of programming interfaces that allow custom-integrated positioning and alignment solutions to be easily programmed in the development language of choice.

A range of video tutorials is available to help explain our APT system software. These tutorials provide an overview of the software and the APT Config utility. Additionally, a tutorial video is available to explain how to select simulator mode within the software, which allows the user to experiment with the software without a controller connected. Please select the APT Tutorials tab above to view these videos.


Kinesis Version 1.14.47

The Kinesis Software Package, which includes a GUI for control of Thorlabs' Kinesis and APT™ system controllers.

Also Available:

  • Communications Protocol
Software Download


APT Version 3.21.6

The APT Software Package, which includes a GUI for control of Thorlabs' APT™ and Kinesis system controllers.

Also Available:

  • Communications Protocol
Software Download

The APT video tutorials available here fall into two main groups - one group covers using the supplied APT utilities and the second group covers programming the APT System using a selection of different programming environments.

Disclaimer: The videos below were originally produced in Adobe Flash. Following the discontinuation of Flash after 2020, these tutorials were re-recorded for future use. The Flash Player controls still appear in the bottom of each video, but they are not functional.

Every APT controller is supplied with the utilities APTUser and APTConfig. APTUser provides a quick and easy way of interacting with the APT control hardware using intuitive graphical control panels. APTConfig is an 'off-line' utility that allows various system wide settings to be made such as pre-selecting mechanical stage types and associating them with specific motion controllers.

APT User Utility

The first video below gives an overview of using the APTUser Utility. The OptoDriver single channel controller products can be operated via their front panel controls in the absence of a control PC. The stored settings relating to the operation of these front panel controls can be changed using the APTUser utility. The second video illustrates this process.

APT User - Overview
APT User - OptoDriver Settings

APT Config Utility

There are various APT system-wide settings that can be made using the APT Config utility, including setting up a simulated hardware configuration and associating mechanical stages with specific motor drive channels. The first video presents a brief overview of the APT Config application. More details on creating a simulated hardware configuration and making stage associations are present in the next two videos.

APT Config - Overview
APT Config - Simulator Setup
APT Config - Stage Association

APT Programming

The APT Software System is implemented as a collection of ActiveX Controls. ActiveX Controls are language-independant software modules that provide both a graphical user interface and a programming interface. There is an ActiveX Control type for each type of hardware unit, e.g. a Motor ActiveX Control covers operation with any type of APT motor controller (DC or stepper). Many Windows software development environments and languages directly support ActiveX Controls, and, once such a Control is embedded into a custom application, all of the functionality it contains is immediately available to the application for automated operation. The videos below illustrate the basics of using the APT ActiveX Controls with LabVIEW, Visual Basic, and Visual C++. Note that many other languages support ActiveX including LabWindows CVI, C++ Builder, VB.NET, C#.NET, Office VBA, Matlab, HPVEE etc. Although these environments are not covered specifically by the tutorial videos, many of the ideas shown will still be relevant to using these other languages.

Visual Basic

Part 1 illustrates how to get an APT ActiveX Control running within Visual Basic, and Part 2 goes on to show how to program a custom positioning sequence.

APT Programming Using Visual Basic - Part 1
APT Programming Using Visual Basic - Part 2


Full Active support is provided by LabVIEW and the series of tutorial videos below illustrate the basic building blocks in creating a custom APT motion control sequence. We start by showing how to call up the Thorlabs-supplied online help during software development. Part 2 illustrates how to create an APT ActiveX Control. ActiveX Controls provide both Methods (i.e. Functions) and Properties (i.e. Value Settings). Parts 3 and 4 show how to create and wire up both the methods and properties exposed by an ActiveX Control. Finally, in Part 5, we pull everything together and show a completed LabVIEW example program that demonstrates a custom move sequence.

APT Programming Using LabVIEW -
Part 1: Accessing Online Help
APT Programming Using LabVIEW -
Part 2: Creating an ActiveX Control
APT Programming Using LabVIEW -
Part 3: Create an ActiveX Method
APT Programming Using LabVIEW -
Part 4: Create an ActiveX Property
APT Programming Using LabVIEW -
Part 5: How to Start an ActiveX Control

The following tutorial videos illustrate alternative ways of creating Method and Property nodes:

APT Programming Using LabVIEW -
Create an ActiveX Method (Alternative)
APT Programming Using LabVIEW -
Create an ActiveX Property (Alternative)

Visual C++

Part 1 illustrates how to get an APT ActiveX Control running within Visual C++, and Part 2 goes on to show how to program a custom positioning sequence.

APT Programming with Visual C++ - Part 1
APT Programming with Visual C++ - Part 2


For assistance when using MATLAB and ActiveX controls with the Thorlabs APT positioners, click here.

To further assist programmers, a guide to programming the APT software in LabVIEW is also available here.

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