Precise imaging makes today’s most advanced medical procedures possible. For example, this physician-controlled C-Arm enables safer and more precise fluoroscopic imaging during surgical, orthopedic, critical care, and emergency care procedures. But, to do so, it needs to produce a consistent stream of high-resolution images while handling the machine’s numerous intricate movements. Elmo’s advanced motion control solution makes it work.

Read this case study to learn about

  • Elmo’s multi-axis network controllers that perform complex, real-time calculations, freeing up computer application resources
  • How an advanced control algorithm guarantees precise movement of a C-ARM
  • How small servo drives enable compact, lightweight equipment
  • Built-in TUV certified Safety functionality in the form of safe torque off (STO).


C-Arms have become a vital tool in advanced healthcare delivery. Used in fluoroscopic imaging during surgical, orthopedic, critical care and emergency care procedures, they enable precise control, immediate responsiveness and most importantly, enhance patient safety.

The doctor has direct control of the C-Arm’s movement around the patient via a console/foot-switch that controls all operating modes and movements in real time. Employing a counterbalanced, isocentric design that allows orbital rotation, it enables virtually unlimited projection possibilities. The C-Arm maintains a constant distance between the imaging source (e.g., x-ray) and the body region being imaged. The central beam always remains in the isocenter, saving procedure time and reducing dosage to the patient.

Machine requirements

The C-Arm’s motion is controlled by a computer application that receives the doctor’s input from the console. Other applications acquire, process and present high-resolution images that the doctor can see while working, improving his/her ability to perform medical procedures. The company needed a solution that could deliver uncompromising quality, producing a consistent stream of high-resolution images while handling the numerous intricate C-Arm movements.

The Elmo Motion control solution includes:

The company chose Elmo’s Gold Maestro network controller to address its challenges. While all motion control commands to the C-Arm are still streamed through the computer application, their numerous complex, real-time calculations are orchestrated by Elmo’s Gold Maestro network controller with Elmo’s closed-loop solution, freeing the computer application resources to focus on rapid image acquisition, processing, and presentation.

Gold Maestro is the most advanced multi-axis network controller and works with any of Elmo’s power-dense servo drives. Its distributed topology enables an intelligent and modular design in which a motion control network comprised of nodes, each consisting of a servo drive with a unique EtherCAT identity, can be closely controlled and monitored by the controller. This enables seamless integration of the appropriate servo drive for each axis, providing highly accurate and responsive motion control. With Gold Maestro at the helm, servo drives can control and monitor each and every C-Arm motion. The overall motion system is extremely efficient while retaining a compact design.

In addition, Gold Twitter drives were installed on each axis of the C-Arm. The drives as small as a matchbox and weighing as low as 18-22 grams actually reduced the overall weight of the moving parts, and increased the system’s rigidness. All drives are chained with an EtherCAT network to Elmo’s Gold Maestro master controller which manages the system in 500µSec cycle time. Elmo’s small yet powerful drives incorporate just the right algorithms to satisfy the need for speed, precision, accuracy and performance of the C-Arm.


The Elmo solution brings all the benefits of industrial experience and standards to the C-Arm. Elmo drives power the motions of the C-Arm with top precision at any voltage, enabling optimal operation and low patient dosage during care procedures. The computer application can focus on imaging while Gold Maestro orchestrates the motion control network, and every Elmo servo drive controls its specific axis with the greatest precision. Moreover, the solution provides exceptionally high mean time between failures (MTBF), ease of implementation, operation, and upgradability.

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