In nearly every case, the FORSIS IPCs work as the connection point between data sink and data source, between acquisition side and processing station. The data is entered manually or read in via a direct connection of controls and machines. For manual entry, identification devices are used to ensure fast and correct entry. Mostly, bar code scanners are used. In addition, contact-free acquisition devices are gaining more and more importance.
The transponder technology (also RFID; radio frequency identification) is based on an electromagnetic procedure and is a method for reading and storing data without contact being necessary. The data is stored on so-called RFID tags – often also referred to as transponders. For lower frequencies, this is carried out inductively, for higher frequencies via radio. The distance over which a day can be read out varies due to the design (active/passive), the frequency band used, the signal strength and environmental influences. Depending on the technology, the distance is between a few centimetres and a maximum of 80 centimetres for passive tags, and up to 100 metres for active tags. If the chip itself is very small, too, the size is determined strongly by the antenna (depends on the frequency or wave length) and the housing (particularly its protection class).
Low frequencies – LF (30-500 KHz).
These systems have a small range and long transmission times; however, they are low-cost and thus are suitable for access controls, engine immobilisers and warehouse management, for example (often 125 kHz = LF), e.g.: hitag™
Medium frequencies – HF (10-15 MHz)
have a short to medium range, medium transmission speed, medium to low price range In this frequency range, the so-called smart labels are used (mostly 13.56 MHz = HF), e.g.: mifare® or LEGIC®
High frequencies – UHF (850-950 MHz, 2,4-2,5 GHz)
have a high range, fast reading speed; however, prices increase rapidly for higher performance of the systems. Used, for example, in the area of automated toll systems and freight wagon identification. Typical transponder frequencies are 125 kHz, 134 kHz, 13.56 MHz, 868 MHz, 915 MHz, 2.45 GHz and 5.8 GHz. Most RFID tags send their information in plain text; some models, however, also have the option of transmitting their data encoded.
