Wireless technology makes use of devices that allow us to communicate without using cables or wires and it plays a role in solving complex engineering problems. With this platform machines can communicate over long distances, with benefits such as cost-effectiveness, freedom from wires and easy setup. By using modern, standards-driven wireless technologies, designers and machine users have access to new tools that can help transform and simplify their working lives. Brett Binnekade, Festo South Africa applications engineer, talks to us about wireless technology in the automation industry.
The benefits of wireless over long distances
Despite the many benefits that wireless technology can claim, distance is a factor that should be considered when machine users purchase wireless solutions. At long distances, the cost and simplicity benefits trump their counterparts by negating cost and sometimes impossible cable runs. When used at a short distance, for example 10 to 15 metres, the benefits of wireless usually do not outweigh the challenges. The cost and complexity of a short distance wireless solution are often much higher than the short cable in its place, even for difficult applications such as a continuously rotating indexing table, where the use of a slip ring has proven to be more robust.
Are wireless solutions part of Industry 4.0?
Wireless solutions play a significant role in Industry 4.0, contributing to improved adaptability, resource efficiency and integration of supply and demand processes between factories. When deciding whether a wireless solution is part of Industry 4.0, factors to consider are interoperability of products from different suppliers, transparency and easy connection of network participants. Another possibility is to check whether the device can move diagnosis and big data from the shop floor level to the cloud via standardised protocols like MQTT and OPC UA or AMQP.
IO-Link for wireless technology
Wireless solutions must not only conform to a specific company’s IO-Link standards but also international standards. IO-Link for wireless technology defines wireless communication between sensors and controllers. It can be integrated into a range of products to avoid cabling. When incorporating wireless technology, it is vital to adhere to a standard that does not lock you in and prevent communication between brands, types and models.
Dangers of using 2,4 GHz
The 2,4 GHz band found in most wireless devices provides coverage at an extended range. Many WiFi-enabled technologies in the automation industry, as well as in household devices, use the 2,4 GHz band. These include microwaves, Bluetooth, garage door openers and many others. Due to the large bandwidth consumed by WiFi devices nowadays, as little as three Wi-Fi hotspots in an area can completely consume the 2,4 GHz band. This is a problem because when multiple devices attempt to use the band at the same time overcrowding occurs, resulting in system faults and downtime.
Frequency blacklisting and adaptive frequency hopping
With more wireless products becoming available, existing frequency channels are becoming more congested. All the wireless devices Festo uses operate within frequencies that have been set aside for free use and are called ISM bands. These are heavily congested, especially the 2,4 GHz one. Devices fight for channels to communicate over. Binnekade adds that most devices use a shotgun approach and transmit on randomly selected channels. If the transmission does not get through, they try again and again, which causes more delays and congestion.
This phenomenon is known as noise or interference. This is where frequency blacklisting and adaptive frequency hopping come in. A device must have the intelligence to check which frequencies are being used and select available channels in every transmission cycle. The lack of these features can heavily impact the performance and stability of a machine or plant.
In the automation industry, reliable and effective solutions are required to keep production moving. However, it is of utmost importance to identify your machine requirements and do the research to make an informed decision. With wireless solutions, always consider how interference will affect the process. Besides wireless technologies, you can also explore digital solutions such as the Festo Motion Terminal VTEM, which solves real industry challenges.
“These are some of the critical points that you need to be aware of before making a purchase. It is also important to understand that when a device is deemed wireless, this is for data communication. The device will still require electrical power and if the device incorporates pneumatics, it will require an air supply line,” concludes Binnekade.
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