Open search

Functional safety

CANopen encoder without SRDOs

TWK provides functional-safe (PL d) encoders, which uses proprietary PDOs instead of SRDOs as specified in EN 50325-5.

The NOCNS3 encoder features SIL-2 (Source: TWK)

The launched encoders comply with a Safety Integrity Level of 2 equivalent to a Performance level of d. It has been developed for customer not requiring CANopen Safety (EN 50325-5, formerly CiA 304). The CANopen Lift protocol transports safety-related process data by means of SRDOs (safety-related data objects). The introduced rotary encoders use periodically transmitted PDOs (process data objects). These PDOs contain the position value plus an 8-bit sequence number and a 24-bit CRC. The number is decremented by 1 with each newly determined position value. The position and the counter value are CRC-protected. The receiving device, for example a host controller or drive, checks the periodical transmission and the integrity of the received process data.


Publish date