The system
Unidirectional signal transmission
The wireless signal transmission system RAD-ISM-2400-SET-UD-ANT can process 4...20 mA analog signals and 5...30 V AC/DC digital signals. Using the unidirectional method, these signals are transmitted to a license-free ISM bandwidth. This bandwidth in a frequency range of 2.4 GHz is free for the use of signal transmission almost all over the world.
Safe and reliable transmission with FHSS
An FHSS (Frequency Hopping Spread Spectrum) technology is used for transmitting the signals. With this technology, transmission does not take place over a fixed frequency within the frequency bandwidth. Instead, the transmission frequencies are constantly changed following a fixed pattern. Since no large volumes of data have to be transported, it is possible to make good use of this technology. If a transmission frequency is disturbed, the data packet that was sent along this frequency is discarded and the outputs are not updated. The outputs are then supplied with up-to-date data on the next frequency. Radio transmission tolerates interferences that lead to a delay, but not to a failure.
The Hopkey - The key to communication
With the unidirectional signal transmission system, it is possible to transmit data from a transmitter to the corresponding receiver. The transmitter and receiver are assigned using the hopkey, which is a compact, pluggable memory chip, in which the sequence of frequencies used in the FHSS transmission procedure are stored. The hop sequence is unique to each set, i.e. there is no other set with the same hop sequence. Based on this fact, it is possible to operate a large number of sets in a joint radio band range without this leading to a failure of the system.
