Integrated operating modes make it easier to adapt to the individual task and practical features make commissioning and servicing much easier. If a high power density and optimized control are then added to the mix, there is no reason why it should not be possible to achieve efficient plants and machines with network fuctionality.
EtherCAT was developed as a real-time Ethernet protocol specifically for industrial use and enables very fast transmission of large amounts of data between the various components of an automation system. It is flexibly scalable and very robust and resistant to interference thanks to the ring structure in communication as well as decentralized design. The ECI-63 internal rotor motors from ebm-papst’s modular drive system are now also available with EtherCAT interface to ensure that these advantages for drive technology can be exploited to the full. To achieve this, a tried-and-tested controller for EtherCAT communication has been installed in the electronics module alongside the power electronics.
The possibilities offered by functions already integrated in the control electronics (K5) can now also be conveniently used in the network and the drives then process complete program sequences independently of the PLC/control system. In conjunction with a safety control system, the TÜV-certified STO (safe torque off) function with performance level D and SIL-2 is also integrated into the drive electronics for torque shutdown in hazardous situations, for example in mobile robots or automated guided vehicles.
Ready for use in no time
When developing the drives, the focus was on the plug & play concept so that the user can get started right away and so that configuration and commissioning effort is reduced to a minimum for individual tasks. The EtherCAT SubDevice Information file (ESI file for short) is available for the drives – this file defines communication between master and slave similar to the Electronic Data Sheet in CAN (EDS for short). This means that a connection to the drive can be established in any development environment and an application can be put into action with just a few clicks of a mouse. If a user wants to control the drive directly from the PLC, pre-assembled structures provide additional support and example programs are also useful for integrating the drive using common motion libraries based on the CiA402 drive profile (CAN over EtherCAT).
In addition, there are three different operating modes: a speed and positioning profile in which the drive calculates its own path, including a homing function, for reference travel. Acceleration and braking ramps can be adjusted individually in this profile. In addition, the “jerk-limited” option means that acceleration processes are as smooth as possible. The latter can be essential for applications in mobile conveyor technology in particular. The “Cyclic Synchronous Position Mode” is also already integrated for precise synchronization of several axes.
Reduced commissioning effort
“Cyclic Synchronous Position Mode” opens up convenient options to the user in practice, as the drive can be integrated as an NC axis at the touch of a button in the popular TwinCAT system manager, for example, and only a few settings need to be changed, such as the maximum encoder resolution or the reference speed. Reference projects, for example, also provide assistance here, as data can be easily be taken over from them and they already contain expertly adjusted speed feed-forward for the controller. All this significantly reduces the programming effort for the user, as has already become evident in practice:
In a mechanical engineering application, different weights had to be lifted depending on the automation solution required by the customer – sometimes one drive can deal with this challenge, but often four or even six are necessary. In the past, the machine builder kept the axes in sync via the PLC and CAN bus, which worked well, but always meant programming and initial configuration effort was required. In TwinCAT, it can now pair the drives with each other much more quickly and keep them in sync, saving a lot of time during machine setup.
MTPA for highest power density
The new ECI-63 drives with EtherCAT interface have even more to offer, for example integrated, field-oriented commutation with MTPA (maximum torque per ampere) increases the power density and ensures higher torques and speeds. The motor is optimally utilized at every operating point and it can be accelerated more quickly or operated for longer at a given operating point. This reduces the thermal load on the motor and means that it consumes less current at the operating point. The basis for this MTPA method is provided by the special design of the rotor with “buried” magnets fixed without adhesive, which support the magnetic field effect significantly better than the usual surface magnets. At the same time, the rotor design ensures low cogging torque.
ID switch for Hot Connect
When designing the ECI-63 drives, the developers took into account another detail that can significantly shorten service times, in other words two additional ID switches. EtherCAT addressing is normally based on the order of the nodes, but thanks to the ID switch, “Hot Connect groups” can be created with a fixed address in TwinCAT. For example, pre-configured sections can be removed from data traffic and added before start-up or during plant operation. After maintenance measures are performed on this type of group, the configuration is immediately available again, without the need for specialist intervention.
The drives are part of ebm-papst’s modular drive system and can be configured within a short time, i.e. combined with gearboxes, encoders, and brakes. Standardization enables short delivery times to be achieved and all drives also meet the requirements of the IP54 degree of protection, and optionally also IP65.
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