Absolute Rotary Encoders from HEIDENHAIN with Mechanical Fault Exclusion for Safety-Related Applications

HEIDENHAIN had developed its newest generation ECN 1123 and EQN 1135 rotary encoders for use in safety-related applications. They are certified for safety-related applications in accordance with SIL 2 (EN 61508) or category 3, performance level d (EN ISO 13849). They also offer mechanical fault exclusion. Their positive-locking hollow shaft features a special fastening element that safely engages a corresponding slot of the measured shaft during mounting and effectively prevents the shaft connection from slipping. The ECN/EQN 1100 series rotary encoders provide absolute values—in the ECN 1123 with a singleturn resolution of 23 bits, in the EQN 1135 with an additional multiturn resolution of 12 bits. Data is transferred over the purely serial, bidirectional EnDat 2.2 interface. In the functional safety version, the ECN/EQN encoders provide two independently formed position values over this EnDat interface. The PFHd value required for the evaluation of safety systems, which indicates the probability of a dangerous failure per hour, lies under 15 x 10-9 for these encoders.

Thanks to their housing diameter of only 35 mm, the ECN/EQN 1100 series rotary encoders in their functional safety version open up new applications. These include uses in servo drive and medical technology as well as in the electronics industry, but also wherever installation space is limited, such as in small servo motors with edge dimensions up to 40 mm. Integrated in the encoder electronics, this area of application also includes the evaluation of an external temperature sensor in the motor winding. The EnDat protocol transfers the digitized temperature value as purely serial data and in this way eliminates two lines in the encoder cable.

Optimized for safety-related applications: The new generation of ECN/EQN series rotary encoders from HEIDENHAIN in functional safety design with mechanical fault exclusion