SCALANCE W – wireless communication with Industrial Wireless LAN

The SCALANCE W products provide a combination of reliability, ruggedness and security in a single product:

• For use by industrial and automation customers
• For outdoor use under demanding climatic conditions
• 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 have modern standard mechanisms for user identification (authentication) and data encryption, and can at the same time be easily integrated into existing security concepts.

Wireless 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 MIMO, high-quality receivers, and fault-tolerant modulation procedures to improve signal quality and to prevent interruption of wireless 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

Mobile end devices, for example, allow a continuous information flow from the management level down to the production level.

The IE/PB Link PN IO with SCALANCE W client modules (e.g. W722) 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 by wireless.

Ruggedness and industrial suitability

The SCALANCE W products can be exposed to fluctuations in the extended temperature range, or to continuous contact with dust and water. Rugged enclosure and mechanical protection against shock and vibration allow use in harsh industrial environments.

EEC (Enhanced Environmental Conditions) series devices are also specially strengthened (coated printed circuit boards resist condensation, increased temperature range) and can also be used in railway applications. Accessories such as antennas, power supply units and cabling are also part of this concept and are suitable for use in industry.

Power and data are transferred over one cable with Power-over-Ethernet (PoE), saving investment and maintenance costs.

The C-PLUG (configuration plug) swap medium stores engineering and configuration data, making device replacement possible in a short time and without specially trained personnel. This minimizes downtimes and saves training costs.

In addition to the functions of the C-PLUG, the KEY-PLUG swap medium allows additional features to be enabled on SCALANCE W78x/W74x and W77x/W73x.

Reliability of data communication

The international standard IEEE 802.11n makes wireless communication via IWLAN even more robust. The greatest advantage is the use of multiple path propagation (Multiple Input, Multiple Output (MIMO)). This allows the devices parallel use of multiple antennas. A higher data transfer rate is achieved and susceptibility to interference in environments with a lot of reflections is reduced.

SCALANCE W products with IWLAN in accordance with IEEE 802.11n support up to three streams each in both the send and receive directions.

Redundant network concepts can also be implemented by wireless. Wireless channels are designed redundantly for this purpose, with a failover time of a few milliseconds, so that the application is not influenced by packet repetitions or interference in the radio channel.

In standard WLAN, access by all nodes to the wireless channel is uncoordinated. This means that access by nodes with critical data cannot be predicted.

The iPCF function (supported by device types with iFeatures) permits cyclic data traffic in real time for several PROFINET IO devices connected by wireless. In addition, this allows mobile nodes to be transferred quickly from one wireless field to another (roaming) so that PROFINET IO communication is not interrupted.

Increased data 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 data rate of 54 Mbps.

Two channels are used simultaneously with the help of channel bonding. Gross data rates of up to 450 Mbps can be achieved in conjunction with MIMO technology in accordance with IEEE 802.11n.

Increased data rate on IWLAN in accordance with IEEE 802.11n with the help of channel bonding