SCALANCE W – wireless communication with Industrial Wireless LAN
The SCALANCE W products offer the combination of reliability, ruggedness and security in one product:
- For implementation at industrial and automation customer sites
- For outdoor environments with demanding climatic requirements
- For low-cost integration in the control cabinet or in devices
The Industrial Wireless LAN (IWLAN) technology provides an extension to the IEEE 802.11 standard that is particularly suited to demanding industrial applications with real-time and redundancy requirements. This provides customers with a unique wireless network, both for process-critical data and for uncritical communication. SCALANCE W products distinguish themselves by the reliability of their radio channel and the rugged type of construction with high requirements with respect to mechanical durability for which SIMATIC is known. To protect against unauthorized access, the products provide modern standard mechanisms for user identification (authentication) and encryption of data, and can at the same time be easily integrated into existing security concepts.
Radio infrastructure
Instead of copper cables and fiber-optic cables, wireless transmission techniques use radio waves. The propagation characteristics of the electromagnetic waves can differ considerably and depend on the spatial environment with the installed wireless infrastructure.
SCALANCE W modules use techniques such as antenna switchover (antenna diversity), high-quality receivers and fault-tolerant modulation procedures to enhance reception and to prevent interruption of radio communication. Extensions to the IEEE 802.11 standard also permit reliable, wireless transmission from PROFINET, form the basis for wireless safety applications and the transmission of video data with extremely short reply and update data.
Network solution with IWLAN
With mobile data terminals, for example, a continuous information flow from the management level down to the production level is possible.
The SINEMA E software is available for simplified planning and configuration of an IWLAN network with the help of simulation functions. It visualizes clearly and details wireless and device properties, thus reducing the configuring and startup overhead and helping to avoid configuring errors.
The IWLAN/PB Link PN IO is available for wireless-based connection of PROFIBUS devices.
This means that information can be provided quickly, reliably and easily at the right place and at the right time wirelessly.
Ruggedness and industrial suitability
The SCALANCE W products can be exposed to fluctuations in the extended temperature range, or continuous contact with dust and water. Rugged housing and design protection against shock and vibration enable use in harsh industrial environments.
The accessories such as antennas, power supplies and cabling are also part of this concept and suitable for use in industry.
Power and data are transferred over one cable with Power-over-Ethernet, thus saving investment and maintenance costs.
The swap medium C-PLUG (Configuration Plug) saves configuring data, making device replacement possible in a short time and without specially trained personnel. This minimizes standstill times and saves training costs.
Reliability of data communication
The international standard IEEE 802.11n makes wireless communication via IWLAN even more robust. Maximum benefit derives from using multiple path propagation (MultipleInput,MultipleOutput (MIMO)). This allows the devices to use several antennas in parallel. A higher data transfer rate is thus achieved and fault susceptibility in environments with a high number of reflections is reduced.
SCALANCE W products with IWLAN in accordance with IEEE 802.11n support up to three "streams" in the send and receive directions.
Multiple path propagation (MIMO) with SCALANCE W788-1PRO and SCALANCE W788-1 M12
Redundant network concepts can also be implemented wirelessly. Wireless channels are designed redundantly for this purpose, with a changeover time of a few milliseconds, so that the application is not influenced by packet repetitions or interference in the radio channel.
In standard WLAN,all stations access the radio channel in an uncoordinated manner. This means that access by stations with critical data cannot be predicted.
The iPCF function (support from device types with i features) permits cyclic data traffic in real time for several wirelessly linked PROFINET IO devices. In addition, this enables mobile stations to be transferred quickly from one radio field to another (roaming) so that PROFINET IO communication is not interrupted.
However, WLAN also provides a transmission mechanism based on standard WLAN in accordance with IEEE 802.11, which makes a defined data rate available to all stations. This means that accessby all stations can be predicted.
Increased transmission rate
WLAN systems in accordance with IEEE 802.11a/b/g/h use a single channel for sending and receiving data. This achieves a maximum gross transmission rate of 54 Mbit/s.
Two channels are used simultaneously with the help of channel bonding. Gross transmission rates of up to 450 Mbit/s can be achieved in conjunction with the MIMO technology in accordance with IEEE 802.11n.
Increased transmission rate on IWLAN in accordance with IEEE 802.11n with the help of channel bonding