Digital motor feedback interface allows communication between frequency converters and motor feedback systems via just two wires

HIPERFACE DSL^® – the digital evolution for electrical drives
SICK is well on the way towards setting a new market standard with its new, purely digital, motor feedback interface HIPERFACE DSL^® (Digital Servo Link). HIPERFACE DSL^® allows communication between frequency converters and mo-tor feedback systems via just two wires. Beyond the corresponding cost effectiveness, maximum safety standards are implemented with HIPERFACE DSL^® because the interface has been technically developed up to the SIL3 level in compliance with IEC 61508.

Experts confirm that “the future belongs to the purely digital protocol because the new HIPERFACE DSL^® interface saves money and reduces the space required whilst offering maximum investment security and machine safety. It thus meets all prerequisites for establishing itself as the interface standard of the future for motor, controller and system producers, as well as machine constructors and their end-customers.”

No detours: motor feedback direct via the motor cable
Servodrive systems in electrical drive engineering consist of, among other things, the two components controller and motor. Up to now, these have been connected to one another via two separate connection cables – for energy supply and data transmission. Combination of the two cables, and thus getting rid of one of the two connection plugs, has been a frequently expressed wish of many motor and controller producers. With HIPERFACE DSL^®, for the first time, the entire motor feedback communication now takes place via the motor cable alone. For this purpose, data transmission has been modulated to the power supply voltage. Special processes and the use of pulse transformers ensure that the encoder signal has been decoupled from noise on the motor power cable. The interface itself complies with the RS485 standard with a transmission rate of 9.375 MBaud. Data communication takes place over distances of up to 100 m and synchronous to the controller clock pulse which, in extreme cases, is just 11.95 µs short. With a view to the increasing safety requirements also demanded in electrical drive engineering, SICK has designed the new interface for the SIL3 level in compliance with IEC 61508.

What HIPERFACE DSL^® provides
Just one cable now, just one motor feedback connection plug now – this is the first thing one notices on looking at the device. Less space required, less cabling effort – this is the result for the user. Further advantages include no need for analog components, an additional connection option, e.g. for a temperature sensor, and much simpler implementation of the motor feedback system through the use of FPGAs (Field Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits). Motor, controller and system producers also profit from optimization of the control circuit through automatic synchronization to the controller clock pulse and from greater freedom regarding motor design – a particularly important aspect when small servomotors are involved.

First motor feedback systems with DSL successful on the market
In product terms, SICK is offering the world’s first sensors of this type with the HIPERFACE DSL^® interface: the EKS36 singleturn motor feedback system and the EKM36 multiturn version. They are designed in the familiar housing diameter of 36 mm so that no mechanical modifications of the servodrive are necessary. Regarding safety, it is important that both motor feedback systems are certified to SIL2 according to IEC 61508. All in all, both the sensor technology and the electronics of the EKS36 and EKM36 motor feedback systems, as well as their new digital interface, offer a high level of accuracy, availability, future orientation and investment security.

The success of the first EKS36 and EKM36 motor feedback systems with the new HIPERFACE DSL^® interface standard shows that the digital path is the right one – the advantages regarding technology, cost-effectiveness and investment security are simply too great.