5.1 The ISM band radio frequency
The Moeller RF system works on a frequency of 868.3 MHz. The advantage of this frequency in the special ISM Band is that throughout Europe, it is approved only for building services automation and barred for other general radio applications. The maximum transmitter power and the maximum duration of the radio signal are fixed. For example, a transmitter may transmit with a maximum of 25 mW (Moeller only transmits with 1 mW!!!), and for a maximum of only 36 seconds in one hour (also referred to as Dutycycle <1% Thus a blocking of the frequency range by continuous transmitters can be completely eliminated, and it is very unlikely that the signals will collide with those of other transmitters.
In contrast, radio systems working on 433 MHz are far more susceptible to interference as a result of the multitude of different facilities transmitting. Also, many of these do not use coding and use only unidirectional processing. As a result, faults resulting from interference from neighbouring facilities or CB radios cannot be eliminated.
5.2 Reliable transmission
Nevertheless, Moeller employs coding and bidirectional procedure as further measures to ensure reliable transmission. This means that a check is carried out to ensure that the messages transmitted have been received correctly and in their entirety. Bidirectional means that the receiver sends an acknowledgement back to the transmitter to confirm receipt of data packets (messages). If a transmitter (sensor) receives no acknowledgement from the receiver (actuator), it repeats the command up to three times.
5.3 Two modes for assignment of radio components
As mentioned in Section 3.2, there are two possibilities for
assigning the sensors to the actuators, depending on the complexity of
the planned RF system:
- manually via the simple "Basic Mode" (without routing function)
- software-assisted via the versatile "Comfort Mode" and extended "Professional Mode" (both with routing function).
For a detailed description, see Section 9 Configuration and start-up.
5.4 The routing function
In the routing function in Comfort Mode, Moeller utilises the capability of the actuators to transmit in order to pass on information to actuators, which can no longer be reached reliably with a direct radio signal. The routing actuators can be actuators assigned to other circuits, and they can assume the routing function for several independent circuits.
