Encoders for patient comfort, functional safety

Motion, Design & Automation - Motion, Automation & Design

Heidenhain encoders provide reliable position measurement for medical technologies.


Patient positioning and laboratory automation seem like completely different medical technology fields. However, both applications require small encoders with high position accuracy, absolute measurement without backlash, high reliability, failure safety, and ruggedness.

Comfortable, accurate imaging

ECN 1123 and EQN 1135 rotary encoders with functional safety ensure high availability.

Examination tables on modern computed tomography (CT) or magnetic resonance imaging (MRI) machines move for positioning, so motion must be measured and controlled in various directions. The table’s height, for example, can adjust to meet the patient’s reach before moving into the scanning area.

Once in the diagnostic machine’s scanning area, the patient must be brought into exact position for examination, requiring longitudinal and transverse positioning and adjustment to inclination.

Heidenhain’s LIC 2100 exposed linear encoder with absolute position measurement ensures smooth motion, providing patient comfort as well as advantages for liquid handling in the lab. By directly measuring the absolute position constantly without a reference run and by transmitting high-resolution position values, the encoders permit highly dynamic closed-loop control of the drives. Acceleration and deceleration are barely perceptible, resulting in smooth and comfortable movements for the patient.

Heidenhain ECN 1123 and EQN 1135 rotary encoders with functional safety allow self-monitoring and self-diagnostics, delivering data for preventive servicing and maintenance intervals. The EnDat 2.2 interface permits online diagnostics of the encoders’ operating status for high availability of expensive diagnostic imaging equipment.


Automated lab sample transfer

Modern, highly automated medical laboratories analyze tiny individual samples in large batches within a short amount of time. Wells on microtiter plates are shrinking and being closely spaced, and large sample batches can be analyzed with minimal expensive reagents.

Laboratory equipment, such as automated pipettors for liquid handling demand precise control (pictured, page 22). One faulty liquid transfer could destroy valuable and possibly irreplaceable samples.

LIC 2100 absolute linear encoders provides exact position data for the pipettes in a pipettor. High encoder resolution and rapid data transfer to and from the control using the EnDat serial interface permit accurate positioning while ensuring smooth, steady control for jerk-free sample movement.

Linear encoder

With high reliability and 15µm/m accuracy grade, the LIC 2100 exposed linear encoder provides accurate position values directly after equipment switch-on, without a reference run. Its measuring standard resists contamination and wear, and the encoder’s scanning head’s IP67 rating protects against dust and moisture for long-term, reliable operation. Measuring lengths up to 3,020mm are available, with specialized solutions up to 6,020mm. This allows accurate monitoring and control of long control and measurement distances in linked laboratory lines.

Safety applications

ECN 1123 and EQN 1135 absolute rotary encoder versions are certified for safety-related applications in conformity with SIL 2 (EN 61508) or Category 3, Performance Level d (EN ISO 13849).

They feature mechanical fault exclusion. Positive-locking hollow shafts securely lock into a corresponding groove in the drive shaft during mounting, preventing slippage in the shaft connection.