Electrical drives not only drive machines, but they have also driven PROFIBUS. In this way, they have propelled the most recent DP-V2 functionalities: 'clock cycle synchronisation' and 'slave-to-slave communication'. They have opened up entirely new applications for drives with PROFIBUS. Decentralised automation structures can be realised economically by means of intelligent drives, since PROFIBUS now also permits the highly dynamic distribution of the technological signals among the drives. Digital servo-drives can now be synchronised via PROFIBUS, and the position control loop can be closed via the bus. This allows demanding motion control tasks to be realised.
Distributed automation by clocked processes or electronic shafts
To realise such applications as 'electrical drives','curve disc', 'angular synchronous process' and 'flying saw', both slave-to-slave communication and clock-synchronised communication are employed.
The integration of drives into automation solutions depends strongly on the task of the drive. To simplify the overview, PROFIdrive defines application classes to which most applications can be assigned.
In the simplest case, the drive is controlled via a main setpoint (e.g. rotational speed) by PROFIBUS. The complete closed-loop speed control is carried out in the drive controller. This application case is employed primarily in the area of conventional drive technology (e.g. in conveying systems).
The standard drive with technological functions is a very flexible variant for realising automation applications. This involves breaking down the entire process of automation into several small subprocesses. The automation functions are no longer located exclusively in the central automation device, but are also distributed in the drive controllers. In this regard, PROFIBUS serves as the technology interface. As one might expect, the distribution assumes that communication is possible in all directions, that is, also slave-to-slave communication between the technological functions of the individual drive controllers. Significant real-life applications include, for instance, setpoint cascades, winders and applications for the synchronisation of rotational speed for continuous web processes.
In addition to the drive controller, the drive also contains a position controller. Positioning tasks are forwarded to the drive controller and started by PROFIBUS. Position drives have a very wide scope of application.Applications include, for example, the twisting on and off of lids in a bottling plant,
or the positioning of knives in a foil-cutting machine.
