Addressing wireless safety in automation
Wireless networking in automation continues to grow as users recognise the many practical benefits. However, the adoption of wireless safety in automation has been slower. Signal reliability, security and range are the leading inhibitors to wireless adoption for safety applications. But according to a white paper from Schneider Electric, this is due mainly to perceived problems rather than reality.
Wireless safety in automation
A factory floor provides challenges to wireless networking, which, if not properly considered and managed, can lead to reliability problems. For example, radio transmission is susceptible to interference, particularly when line of sight is obstructed by equipment. However, these concerns are being overcome for wireless safety applications by rigorous assessment and proven technology.
Firstly, greater use of 2.4GHz frequency equipment due to its signal reliability being stronger than the traditional lower frequencies. The emergence of new, high reliability wireless technology will help. Bluetooth Low Energy (LE), further improves confidence in the reliability of mobile wireless control systems. Bluetooth LE uses a floating frequency hopping mechanism, to avoid interference from devices operating on the same frequency channels.
Maintaining network availability often means the use of high frequency network protocols, which can limit the range of communication. The latest advances in wireless technology use smart antenna to solve this issue. They work by increasing or decreasing the system’s working distance to the adapted values for the specific application. In wireless remote-control in safety applications, it is also important to limit the working range to the precise area where the operator can control the machine.
As more wireless remote-control systems come into use, concern over data and network security grows. OEMs and end-users must adopt a multi-layer security approach, which provides numerous barriers and levels of protection.
Particularly with safety applications, the reliability and security of the system must be paramount. The use of specific functions, such as code sequencing and encrypted communication, help to protect against external attacks. Guarding against non-malicious intrusions, requires educating operators and providing clear operating procedures.
Wireless remote-control systems must be compliant with the relevant standards. These can be general standards about radio emissions and functional safety, or for specific types of machinery. The 2.4GHz frequency band has universal acceptance and doesn’t need a specific license for use worldwide.
Wireless technology is emerging as acore technology. Wireless safety control systems in critical safety applications will increase in applications where operator mobility is beneficial to both safety and productivity. Limitations of the past have been overcome and numerous advantages are now available to both end users and OEMs.
Go here for Schneider Electric’s white paper “Wireless Technology-Changing the face of safety applications”
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