Munich, Germany - Dunkermotoren has now gone a step further with the master functionality (MI - Master Integrated) integrated in the BG series of compact drives. A compact drive with integrated master functionality " complemented by additional DC drives " makes it possible to set up an independent drive network, where the master drive takes over the function of the higher-level PLC. All the data for positioning the individual drives is stored in its electronics. These can be up to eight BG series compact drives with different sizes and output power. The master drive has a flash memory, where all the data for the independent network is stored in the non-volatile memory. Sequence programmes are written in a deterministic high-level language and stored in the memory. The programming language uses standard objects in accordance with CIA DS302. Up to 500 command lines are available in the flash memory, for extensive motion and monitoring functions. A command line, in turn, can contain several functions. This way, even complex motion profiles can be realised within the independent master-slave drive network.
DC drives with integrated electronics in modular system
A significant advantage of this local drive network is that it relieves the higher-level PLC of drive-specific control and monitoring tasks. Simply selecting a motion sequence stored in the master drive's flash memory is all it takes to initiate this sequence within the network. So these drive tasks are performed largely independently of the cycle times of the higher-level PLC. In many applications, this reduces the achievable cycle times. In addition, some time-critical applications can now be realised with a comparatively simple, affordable PLC, as the local independent network relieves the PLC of processing and monitoring tasks. The PLC is connected to the network via CANopen. Within the drive network, the individual drives also communicate via CANopen, in accordance with hardware standard DSP402, which substantially minimises wiring costs. What's more, the higher-level controllers need less room in the central cabinet. Because of the simplified installation, machine manufacturers can build up and deliver their machines more flexibly and in shorter lead- times. The BG series DC servo motors function as slaves also incorporate the electronics for data exchange so ensuring fast and reliable data exchange within the local drive network. For example, dependent on the master drive, each slave drive independently positions carriages for format adjustment on profile milling machines. Depending on the input from the master drive, their integrated electronics independently control speeds, pre-configured acceleration and deceleration, and the positions to be approached. To achieve good positioning accuracy here, the control loops operate at up to 1024 pulses per revolution.
Users can choose from a wide range, extending from 20 to 550 watts output power. So machine manufacturers can design drives for the required tasks. DC drives with lower ratings are normally adequate for simple sliders. Where higher ratings are called for, and consequently where much more expensive AC servos have previously been used, the BG75 series brushless DC servomotors with drive ratings up to 550 watts can now be used.