"Servo controllers as a component of servo drives should become smaller and smaller and their power density should become higher and higher," explains Karlheinz Wirsching, Product Manager and Head of Technical Sales Converters at Baumüller in Nuremberg. "We are therefore presenting a new generation that almost doubles the power density compared to the previous generation, i.e. an almost doubling within a single size. This means that we are gradually reaching the point where the devices can no longer be made smaller, because otherwise you won't be able to fit the connectors."

However, the increasing cable density is just one of several technical trends that can be seen in servo controllers. "We have been seeing a trend towards flexibility for some time now: a servo controller must be designed in such a way that it can be used to meet different customer requirements quickly and easily," explains Karlheinz Wirsching. "The devices must therefore be scalable." In addition, they must be as modular as possible: "Machine builders no longer plan their machines as a uniform complex, but divide them into individual machine modules. The servo controller must map and support this type of modularity." The third aspect that has been visible for some time is cost and energy efficiency.

These long-term developments have recently been joined by a trend towards consistency: "Users no longer want to have to use different software programs to parameterize or program something. Nowadays, all of this should work from one modular program. In the same way, it must be possible to set the IP addresses of the automation devices in a system from a central point so that the system can then distribute the addresses to where they need to go."

Karlheinz Wirsching considers openness to be another important point: "A servo controller has to map a wide variety of communication interfaces in the system, whereby the basic initialization must be automated." In discussions with customers, he is also increasingly hearing the topic of IoT capability: "Collecting and processing data; communication, whether via OPC UA, Ethernet or tunneled through a fieldbus - the servo controller must have all of these options." In this context, the servo controller is being used more and more as a sensor: "Power calculation of the network, power calculation inside it, power calculation on the motor - these are three important values that can be used to calculate the efficiency of the system. Or I can see from the current that the motor bearing is broken." Last but not least, servo controllers must support the trend towards increasingly intelligent drives: "In order to be able to build modular machines, you need servo controllers with an integrated controller that controls the machine module and provides information upwards."

Karlheinz Wirsching, Baumüller: "A servo controller must map a wide variety of communication interfaces in the system."

© Baumüller

Baumüller's new "b maxx 6000" generation of servo controllers reflects these trends. The "b maXX 6300" modular devices and the "b maxx 6500" mono devices are available. The mono units are far more compact than the members of the predecessor family: size 4, for example, with a power range of up to 75 kW, achieves a 48% reduction in installation volume while almost doubling the power density at the same time. The "b maXX drivePLC", according to Baumüller one of the fastest PLCs in drives, is prepared for integration into the new devices, making an external PLC superfluous. Various encoders as well as hardware and safety options are also available. For encoders, users can choose between resolvers as well as optical and purely digital encoders with all common interfaces. Hardware options include signal transmission bus, service option, digital and analog I/Os and brake connection. In terms of safety, different variants are available, from simple hardware-controlled STO (Safe-Torque-Off) to higher safety functions controlled via FSoE (FailSafe over EtherCAT). This scalability means that there is a wide range of expansion stages from the basic device to the fully equipped version.