Safety encoder is `the first`
The German encoder manufacturer Heidenhain claims to have developed the first position measuring system for safety applications based on serial data transmission. At the recent SPS/IPC/Drives show in Germany, it unveiled a range of rotary encoders for drive applications that transmit absolute position data using two independently generated position values which are compared against each other.
The position measuring system (shown below) consists of the encoder, a data transmission line using Heidenhain`s EnDat 2.2 serial data transmission protocol, and a receiver with monitoring functions located in a safety controller. The safety technology is designed to meet the requirements of ISO 13 849-1 (previously EN 954-1) and IEC 61 508.
Heidenhain is developing similar systems for absolute linear and angle encoders.
The company has also launched a family of rotary encoders for servo drives that incorporate new optoelectronic scanning and evaluation electronics and are said to be suitable for safety applications, using digital data transmission.
The new scanning system is said to improve reliability in applications such as servomotors where encoders can become contaminated by oil, dust and gases from the motor windings. Unconditioned signals from the scanner are converted directly to digital data, avoiding the need for costly extra interpolation. The signal quality is said to be improved by a factor of four to five.
