The continuous condition monitoring of electrical drives is growing in prominence, as the purely digital Hiperface DSL encoder interface makes it possible to provide status data such as the temperature of servo actuators in a format which can be evaluated by control technology.
By Clemens Bitsch, business development manager, Sick Stegmann, Donaueschingen; and Klaus Oberkötter, MD, TBO.
THE continuous condition monitoring of electrical drives is growing in prominence, as the purely digital Hiperface DSL encoder interface makes it possible to provide status data such as the temperature of servo actuators in a format which can be evaluated by control technology. The fully scalable premo servo actuator platform from Wittenstein motion control not only uses the future potential of Hiperface DSL, but also benefits from numerous design and safety advantages.
We need digital data and protocols to enable us to ‘look into’ a machine right down to the motor shaft. Thanks to their Hiperface DSL interface, motor feedback systems such as the EKS/EKM36 and EFS/EFM50 product families from Sick Stegmann fulfill this prerequisite, which is necessary to ensure efficient condition monitoring. An external temperature sensor can be connected to the encoders and the values from the sensor – together with other process data from the drive such as speed, voltage, mechanical revolutions, or present diode current (for optical EKS/EKM36 and EFS/EFM50) – can be recorded and digitally transmitted to the controller for evaluation.
“All of this makes it possible to derive information about the status and anticipated development of drive and machine conditions,” explained Jörg Peters, head of product management, Wittenstein motion control in Igersheim. “Lots of machine manufacturers are becoming more aware of intelligent, future-proof servo technology at the moment because of the influence of Industry 4.0. With the help of their transmission technology, drive solutions with Hiperface DSL-enabled encoders offer a way of providing data which can be used for continuous condition monitoring and preventive maintenance.”
It is therefore no surprise that Wittenstein motion control offers optional smart motor feedback systems with Hiperface DSL in all equipment packages of the new premo servo actuator platform.
Fully Scalable In Performance-Based Increments: The ‘Premo’ Servo Actuator Platform
With the newly developed, fully scalable premo (precise motion) servo actuator platform, Wittenstein motion control is able to configure motors and gears with application-based performance feature increments from a specific modular system to form customised motor/gear units. “In theory,” said Mr Peters, “this modularity means that there are over 40 million possible premo variants in total.” In terms of drive technology, the premo servo actuators boast exceptional power density. They have also become extremely compact and flexible thanks to the intelligent flex-module system and offer significantly higher torque than the previous model series.
“The equipment packages available – base line, advanced line, and high line – provide high connectivity for every application range,” explained Mr Peters. “In terms of the mechanics, shaft and flange versions are available on the output side; when it comes to the electrics, the spectrum ranges from the analogue resolver – the basic equipment in the premo base line – to the digital Hiperface DSL interface which features in the premo high line as standard.” In order to make digital one cable technology available in all performance increments, the base line entry-level class and the advanced line dynamic class can be optionally upgraded with Hiperface DSL motor feedback systems from Sick Stegmann.
Wittenstein Motion Control Relies On ‘Leading Standard’
For Wittenstein motion control, digital one cable technology is an exciting prospect for many reasons. In terms of equipment, Hiperface DSL halves the need for plug connectors and cables. This not only cuts the number of components in the motor/gear unit, but also reduces the amount of wiring required. Furthermore, when premo servo actuators are integrated in robots, moving axes, or mobile machine structures, the reduction in mass and weight saves kinetic energy and improves the energy efficiency of the entire powertrain.
“In addition, the absence of a second plug connector reduces the risk of fluid ingress in hygienic environments,” said Mr Peters. When it comes to individual applications, each machine manufacturer can configure the premo actuators flexibly to ensure a future-proof communication interface for every task, thanks to the motor feedback systems with Hiperface DSL. Finally, data communication via Hiperface DSL is suitable in terms of safety for applications up to SIL2 in accordance with IEC 61508.
“In my opinion, Hiperface DSL is becoming one of the leading standard protocols in digital feedback systems for servo drive technology,” said Mr Peters in reference to the current market situation. “As the developer of the digital interface, Sick Stegmann is not only one step ahead in terms of the equipment implementation, but is also able to provide support for Hiperface DSL applications and their implementation at its own test laboratory in Donaueschingen.”
Premo + Hiperface DSL: Perfectly Prepared For Condition Monitoring
Servo actuators from the premo platform and motor feedback systems with a digital Hiperface DSL interface make it possible – with the aid of the sensor input on the encoder and a sensor (eg: for temperature measurement) integrated in the drive – to monitor the status and utilisation of the machine part and to use this data for condition monitoring where applicable by means of additional evaluation logic in the control. Motor characteristics, serial and part numbers, as well as additional data that provides ready assistance for maintenance and replacement, can also be transmitted via Hiperface DSL with the help of the electronic type label functionality.
“There are a range of technological, operational, and economic reasons why the operators of machines and systems should familiarise themselves with the planned servo actuator technology and its suitability for condition monitoring without delay,” advised Mr Peters. “The ability to analyse sensor data makes it possible to resolve disruptive factors and causes of damage more quickly.”
The second goal associated with condition monitoring is the optimisation of machine efficiency in order to achieve maximum productivity. “Continuous condition monitoring is essential for this, in order to achieve need-based maintenance and as such optimal machine operation.”
CM Scenarios Already Put Into Practice
Smart servo actuators such as the premo product family with digital motor feedback systems and Hiperface DSL will make it possible to track and evaluate the development of relevant drive and machine parameter trends even more comprehensively in the future. It is already feasible for the motor feedback systems of the EKS/EKM36 and EFS/EFM50 product families to be used to record and evaluate variables other than temperature – humidity, for example. Other scenarios describe how torques, transverse forces, or load profiles can be recorded and reported in order to identify material breakages, bearing damage, or signs of wear in the powertrain at an early stage.
With SHub, Sick Stegmann is working on a multi-sensor concept which makes servo motors even smarter, as the additional sensors provide new information for even more intelligent maintenance concepts. In parallel, there is the possibility of separating control-related and maintenance-related data, so that the maintenance data can be made available as histograms in the cloud via Bluetooth or Near Field Communication (NFC) gateways, for example.
In this way, Hiperface DSL provides the basis for entirely new business models in the fields of Internet of Things and condition monitoring – which can in turn deliver benefits for smart servo actuators if they, like premo, are ‘Hiperface DSL-ready’.