Automation & Control
Diagram 2. At present, the relay contacts of external hardware must be wired discretely onto the individual loads in order to switch them off. In future this will not be necessary, as the loads ‘talk’ PROFIenergy.
retrofitting capability and compatibility, these commands are mapped onto existing, tried and tested PROFINET services. In this case, onto records. These acyclic services do not occupy any additional addresses in the process image. In other words, the useful data quantity structure of a PROFINET device is not modified by PROFIenergy. This means that PROFIenergy can be used in existing program libraries and factory standards, such as those that exist in the automobile industry.
Likewise, the device manufacturers can upgrade their
existing components to PROFIenergy by using a firmware update. This facilitates a swift implementation – even into existing products.
The main benefit for the end user is saving energy and the costs associated with it. Measurements revealed that even during non-productive periods many plant sections still use between 40 and 60 per cent of the energy that is required during actual production (Diagram 1).
Non-productive periods Whereas in operation the focus is on energy-saving products such as motors with a better energy efficiency class, PROFIenergy allows savings to be made predominantly during the non-productive periods. In this case, it is a matter of partially or completely switching off unnecessary systems. Users can expect energy savings of up to 80 per cent.
Diagram 3. Initiation of shutdown by the user by sending the PROFIenergy command and transmission of the length of break. The local intelligence, using the example of a robot here, decides which units can be shut down, in order to remain ready for production on expiration of this period.
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Diagram 4. Calculation of the absolute moment at which the starting command is to be sent to the respective device, so that all devices are ready for operation again at the required time. To calculate this, the startup time previously reported by the individual devices is to be subtracted from the required target time.
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