SMD3 - AML’s brand new single-axis bipolar stepper motor drive

Posted on Wednesday 24th June 2020 at 11:50

SMD3 - AML’s brand new single-axis bipolar stepper motor drive

We are pleased to present to you our new SMD3 Stepper Motor Drive. This is a completely re-designed single-channel stepper motor drive, bringing forward the high performance and reliability of the SMD210, while introducing many new transformative features. Combined with the included powerful configuration and control software, the SMD3 is the best way to control our range of UHV-compatible stepper motors.

The all-new SMD3 single-axis bipolar stepper motor drive has been engineered to operate vacuum-compatible stepper motors with maximum performance while minimising temperature rise, therefore, reducing out-gassing. This is made possible by utilising advanced drive techniques and the addition of the intelligent automatic current profile switching feature. This allows for independent acceleration, run and hold current settings.

Step and current transitions

Configuring the SMD3 is straightforward via the USB Type-C connector. The SMD3 appears as a virtual COM port when plugged in to a PC, enabling configuration and control using the provided user-friendly software, your own application, or any serial terminal program. An extensive list of command references are documented in the SMD3 user manual.

The compact and robust custom steel enclosure includes convenient mounting points, status LEDs and distinct connector labels.

Although designed to take full advantage of our range of UHV-compatible stepper motors, the SMD3 is not limited to operating AML motors. The SMD3 supports many bipolar and universal stepper motors, it can operate motors ranging from small NEMA 14s to large NEMA 23s. The SMD3 is ideal for many applications, including sample manipulation; linear translator, rotary stage and goniometer control; automation; manufacturing.

Our next-generation stepper motor drive has been designed for maximum performance, configurability, and versatility. One power supply provides power to the drive logic and the motor. The motor, switches and power supply can be connected easily with removeable screw terminal connectors. Little knowledge is required to get started with the SMD3; the software provides descriptive explanations of the settings and commands available, and the SMD3 hardware provides thermal, over-current and short-circuit protection to protect the PC, motor or driver from damage.

Advanced users can take full advantage of the extensive features available with the SMD3:

  • Full-step and up to 256x micro-step resolution, with user-configurable transition from micro step to full-step mode (stops on full-step positions only; micro-stepping used for control of resonance and smoother step transition)
  • Acceleration, run and hold current is adjustable from 0 A to 1 A RMS in approx. 30 mA steps
  • 2 x configurable limit inputs
  • Opto-coupled step, direction and enable interface
  • Comprehensive configuration and control software supplied, with the ability to script movement sequences
  • Interface to your own application using serial commands or the powerful C# API

Our SMD3 single-axis bipolar stepper motor drives are manufactured in the United Kingdom and are rigorously tested to ensure that each unit meets our uncompromising requirement for quality and performance.

SMD3 assembly

AML offers a range of products specifically designed to work with our SMD3 Stepper Motor Drive, including our ultra-high vacuum compatible stepper motors, UHV mechanisms, cables and feedthroughs.


Included with the SMD3 is a powerful software package that allows you to easily configure and control multiple SMD3 devices simultaneously. The project wizard automatically scans for connected SMD3 devices and allows you to set a custom name for each device.

Device search animation

Once connected, all settings of attached SMD3s can be viewed and modified using the straightforward graphical user interface. Key figures including motor temperature, position and current are displayed on the device status window. Configure device options such as operation mode, motor currents and limits using the device properties window. The SMD3 can be operated standalone, without needing to be connected to a PC; using the joystick or SDE (step, direction, enable) interface, once your parameters are saved to the device.

Within the SMD3 software, movements can be commanded with the click of a button, using the device controller window; easily toggle between velocity and absolute or relative positioning modes. Manage multiple SMD3 devices. Custom labels can be assigned to each device, for example, the different axes of a gonionometer can be referenced (e.g. ‘Base X’, ‘Base Y’, ‘Tilt #1’, Sample Rotate”). Devices can be added and removed from a project easily.

SMD3 Software

The SMD3 software includes an easy to use script editor, that allows for sequences to be programmed and executed on multiple connected SMD3 devices, as well as system level operations such as adding and removing SMD3 devices from the project.

The scripting language used is JavaScript; this is powerful, easy to use and extensively documented. A global ‘smd’ object is made available from which you perform all interactions with the SMD3s. Type ‘smd.’ and an auto completion popup appears, showing all available commands, as well as help documentation for each. Press the enter key to select an option, then provide any arguments required.

Animation of scripting auto completion

Projects and scripts can be saved to file; quickly reconfigure the system by loading different projects. Panels can be dragged and repositioned. The position of windows and panels is saved within the project file. The fully-featured version of our SMD3 software is free to download here.

For more information about our range of UHV motion equipment, please do not hesitate to contact our dedicated team by emailing