Safety-Related Position Encoders With EnDat 2.2 Pure Serial Interface

The development of safety-related measurement subsystems by HEIDENHAIN Corporation are now available to allow manufacturers of machines with safety as a criteria to easily complete their systems. To do this, HEIDENHAIN supplies high quality encoders with an EnDat 2.2 transmission component (an exclusive digital, bi-directional interface) in order to be a part of a safe drive. This modular system was shown for the first time at the last SPS/IPC automation trade show in Germany. With this encoder/interface combination, machine and plant manufacturers can now have all the benefits of serial data transfer, such as optimization of costs, diagnostic possibilities, automatic commissioning and rapid formation of the position value in safety-related applications. Specifically, HEIDENHAIN’s subsystems for a safe drive consist of: • Encoder with EnDat 2.2 transmission component • Data transfer line with EnDat 2.2 communication and HEIDENHAIN cable • EnDat 2.2 receiver component with monitoring function (EnDat master) Now safety-related systems can be designed with only one encoder per axis provided that the encoder complies with stringent requirements for reliability of the transmitted position value as HEIDENHAIN’s modular subsystems here do. And now that the EnDat 2.2 offers a maximum transmission frequency of 16 MHz, it is an added bonus that it is currently the fastest purely serial interface for position encoders on the market today on the basis of the RS-485 transmission technology. It is also important to note that in the safety-related systems shown by HEIDENHAIN at the SPS/IPC show, the correct interplay with a safe control was ensured. The reliable transmission of the position is based on two position values generated independently from each other and on error bits. Online diagnostics is a unique feature of the EnDat interface as no other encoder or interface system currently offers this. The values are then all provided to the safe control.