Modified angle encoders for functionally safe machine applications from HEIDENHAIN

HEIDENHAIN has updated its angle kit encoder line by modifying the ECA 4000 angle ring encoder series for use in safety-related applications. Of notable use in machine tools where dangerous conditions exist, this new ECA 4410 encoder is also useful in many automation applications such as in robotic arms.

Factors contributing to this new functionally safe ECA 4410 encoder are the EnDat data interface as well as modifications made to the mechanical connection that now includes fault exclusion. Here, the new ECA 4410 drum has a centering collar on the inside diameter, to center it via a fit on the mating shaft. These scale drums also have additional back-off threads for disassembly. This, and if the machine manufacturer adheres to the dimensioning of the mechanical connections, provides fault exclusion for the loosening of the mechanical connection, thus functional safety. This ECA 4410 drum is the only one on the market with where the fault exclusion is ensured under all specified operating conditions.

In conjunction with a safe control, the ECA 4410 can be used as a single-encoder system in applications with control category SIL 2 (as per EN 61508) and Category 3 PL performance level “d” (as per EN ISO 13849-1).

In addition, the ECA 4410 scanning heads were also modified for functional safety with changes to the holes for mounting. The threads for mounting the scanning unit from the back face were expanded and placed a little lower to permit the use of longer screws. Mechanical fault exclusion is ensured if the specified tightening torque and the minimum screw length are complied with.

The new ECA 4410 drums are mechanically compatible with the normal ECA 4000 line as well as the ERA 4000 line of angle encoder feedback devices.

For more information on this series and its relation to functional safety, a brochure is available at www.heidenhain.com.