The use of radio sensors is appropriate whenever direct cabling between the sensor and I/O unit is too time-consuming or too difficult to implement, e. g. for outdoor cabling, or in inaccessible places in the server rack or within the IT infrastructure of data centres (indoors).
This eliminates the need for cabling of the sensors, and the system is easily retrofitted while operational. There is no need to lay any cable trunking or to modify the IT infrastructure. The position of the measuring point may also be altered retrospectively by simply moving the sensor. By connecting the wireless I/O unit to the existing CMC-TC monitoring system, the system may be extended in a modular and flexible manner. In order to optimise radio links, an external aerial may optionally be used on the wireless I/O unit. Similarly, the transmission and reception range may be flexibly extended using additional wireless I/O units as repeaters. There is no need for visual connection between the transmitter and receiver of the wireless network, which likewise serves to increase flexibility.
Plug and play compatibility system
The wireless sensor network is easily set up using plug & play installation. By means of a simple commissioning procedure comprised of a learning mode and learning key, the sensors are taught by the wireless I/O unit via plug & play. Rittal offers a wireless measurement system with digital display for identifying the optimum radio connection for the assembly site. This measurement system has the same design as the sensors and may be connected to the reference location
of the sensor for test purposes.
The wireless sensor network may be used in racks, bayed enclosure suites, IT rooms, buildings, production plants, storage halls, industrial plant or outdoors. It is also suitable for use in inter-disciplinary applications. The wireless I/O unit and the CMC-TC monitoring system must be installed in a Rittal enclosure with an appropriate protection category to suit the application. A protective cover is available for the sensors as an optional accessory to increase the IP protection category.
Long service life
The wireless sensors contain a high-capacitive, long-life lithium primary cell. Thanks to the modern chirp radio transmission system, an exceptionally low level of energy consumption is achieved; while in sleep mode, the current rating is in the micro-ampere range, thereby facilitating a long battery life. Depending on the sensor type, application and ambient temperature, a battery life of up to 5 years is achievable. The battery cell is continually monitored by the system. It is also possible to replace the battery.
Radio transmission occurs within the 2.4 – 2.48 GHz ISM band, which is licence-free for end users. Using so-called chirp impulses (broadband transmission) for radio transmission produces a high level of protection from interference with other radio systems on the same frequency range, such as WLAN, ZigBee, Bluetooth. Additionally, the integral encryption of radio telegrams offers reliable protection from unauthorised monitoring of the data transmission. As well as transmitting the measurements, the connection quality is constantly monitored by means of so-called “live-check” telegrams from the sensor.
The wireless network will behave differently depending on the environment (walls, distances, sources of interference, dynamics). By using additional wireless I/O units as repeaters, the radio connection can be improved/radio links extended.