Control Electronics for a Wall-Mounted Patient Transducer

Client

RAMED Kopřivnice is a Czech manufacturer of medical equipment. It specializes in the development and supply of positioning and transfer systems for operating rooms and hospital wards.

Assignment

RAMED approached us with a request todevelop the complete electrical equipment and control system for the PPZ 01 wall-mounted patient transfer device.

The main goal was to create a fully motorized device built directly into the wall between the non-sterile preparation room and the sterile operating room. This system allows for the safe transfer of a patient from one bed to another across the wall barrier without the need to bring non-sterile beds into the operating room.

Our task was to design reliable electronics and a safe, redundant power supply while complying with the strict medical regulations of the MDR and ČSN EN 60601-1.

Call

The key challenge was Ensuring patient safety under all operating and fault conditions. The device’s lifting drives are electronically synchronized using a specially developed driver with incremental inputs; independent cable-based distance sensors provide additional safety monitoring. Precise and synchronized belt and plate movements are ensured by quiet BLDC motors with drivers connected to the control electronics via an Ethernet interface. The central control unit is connected to a touchscreen display, which, in addition to providing control functions, also offers diagnostics and a “black box” for system error reports.
At the same time, we needed to ensure a safe and reliable power supply for equipment with high current draw from motors when moving patients weighing up to 225 kg. Therefore, we developed a system that uses a 24 V voltage converter with safe, medical-grade isolation (2x MOPP) for power, along with an internal 24 V battery that provides power support and a backup in the event of a power outage.

Another challenge was to ensure absolutely smooth movement, guarantee full electromagnetic compatibility (EMC) with diagnostic equipment in the operating room, and, in the latest version, integrate heating under the stainless steel plate to warm the conveyor belt.

Our solution

We have developed a complete electrical system operating at a safe voltage of 24 V DC. At its core is a control unit that provides feedback control of the motors and ensures the smooth, synchronized movement of both the stainless steel plate and the plastic belt.

We integrated a heating element beneath the stainless steel plate, which heats the sliding belt to ensure the patient’s thermal comfort. The unit includes a touchscreen HMI display, a handheld controller, and a battery management system with 24 V batteries. We have equipped the device with SIL3 safety logic and STOP buttons, and certified it in accordance with the ČSN EN 60601 series of standards.

Result

The result isa Class I certified medical device, whose electrical components we developed back in 2024 and recently expanded to include a heating function for new units. The PPZ 01 transfer unit reliably serves as a hygienic wall partition that prevents contaminants from entering the operating room. The strenuous manual transfer of patients (which previously required up to 4 people) has been replaced by a smooth, motorized transfer that requires only 2 staff members.

The device eliminates the risk of injury to both staff and patients and, thanks to its heated surface, provides a high level of comfort before surgery.

Our control electronics thus provide a functional and cost-effective foundation for mass production.