Industrial communication RFID Systems enable a production with many variants Back to current issue Markus Weinländer Customized products are more and more in demand. However, the step from mass-production to individualized series products particularly affects the production engineering. With RFID, the challenges of producing small lots with many variants can be solved effectively. Author: Markus Weinländer, Head of product management Simatic Ident at Siemens AG, Division Industry Automation, in Nuremberg, Germany In the production, there are a multitude of measures that enable a cost-effective manufacturing of individualized series products. By now it has been accepted that the decentralization of the planning, control and monitoring represents an important strategy for this. Decentralization means that decisions are made at an as low as possible level in the automation hierarchy, i.e., “on site”. Ideally, the work piece should bring along all information about the steps to be performed on it, without necessitating central units for the individual control. This concept ultimately leads to autonomous manufacturing cells, which can perform a specific production step as independently as possible from other units, and also optimize themselves through their ability to learn. However, when utilizing such flexible manufacturing stations, a clear identification of the respective work AUTOMATION TECHNOLOGIES 2/2014
Industrial communication piece is indispensable: After all, the machine has to execute an individualized program for each work piece. The theoretical possibility of predicting every product movement by computer, which work piece is located in which station at the moment, is hardly feasible in practice. Too large are the possible deviations; too complex is the work with regard to the data. Flexible Production – controlled by Radio In practice, various identification systems are being employed, with RFID systems in the high frequency band (HF) having proved particularly effective due to their low costs and very high reliability. Radio technology is unsusceptible to any type of dirt contamination. This makes it interesting for applications where harsh environmental conditions are unavoidable. A second advantage of RFID is the possibility of repeatedly writing to the data medium. In combination with the high storage capacity of RFID transponders (up to 32 kB with the Siemens system Simatic RF300), decentralized automation architectures can be implemented, which greatly reduce the work for the centralized data storage. The concept: RFID transponders with large memory are affixed to each work piece (or work piece carrier) and store all necessary production data, e.g., bill of materials, production instructions, inspection guidelines. At the beginning of a production line, this data is retrieved from the production control system and programmed into the transponder. At the individual production stations, PLCs read this data directly from the RFID readers and utilize it to control the production section. Ideally, no queries to the background systems are required. After carrying out the production step, the PLC can store status and quality data on the RFID transponder, before it is transported together with the work piece to the next station. Various RFID solutions available Siemens offers two RFID product families in the HF area. Simatic RF300 uses a specifically developed radio protocol that communicates eight times faster than standard systems, and the data media can store up to 32 kB of data. The advantage: Even extensive data records can be read very fast – often without having to stop the transponder (and thus the work next page 01 High-performance systems are able to capture transport boxes
