This article is part of the Wireless Wish List series on industrial wireless networks. View the rest of the series here.
Once surveys and assessments are done, many users will discover they must also coordinate with other onsite wireless devices and networks, which have proliferated widely in recent years and penetrated into many unexpected places.
"No one trusted wireless 10 years ago, but now everyone is using Wi-Fi to working remote due to COVID-19," says Justin Shade, senior product marketing specialist for wireless at Phoenix Contact. "The problem that remains is everyone tends to think of wireless as all the same thing or just Wi-Fi and cellular. However, industry uses all different kinds of wireless, such as Bluetooth, Wi-Fi, LoRaWAN, cellular and satellite, and it's important to know where each works best."
Test after assess
Shade reports the typical wireless site assessment and upgrade consists of three basic stages. The first is building requirements, learning what the client wants to do, and deciding what they want to get out of a wireless network and its devices. It's important to talk to the actual users, understand what they're not getting out of their current systems, and learn what they'd like to get out of a new system. There are many stakeholders in industrial automation systems, but not all of them have the same goals when it comes to overall scope.
"An assessment is also needed to determine what types of wireless are already onsite. Physically walking the site is still crucial. This process involves identifying other wireless networks the client may need to coexist with; determining if those other networks can be consolidated into the current project; or deciding if they need to continue to exist as an independent system," says Shade. "Will these existing systems impact the scope of the project? Is there Wi-Fi? Are there other 900 MHz or 2.4 GHz networks? Also, who owns and maintains all this stuff? Once some of these questions are answered, users can begin the second stage, which is selecting the frequencies and technologies they'll need to meet their site requirements and production goals."
Shade explains the three main frequencies are 900 MHz, 2.4 GHz and 5 GHz, which will soon be joined by 6 GHz. If a site or application is already a heavy user of one frequency, then picking another can help prevent interference. "Bluetooth uses 2.4 GHz, Wi-Fi uses 2.4 and 5 GHz, and ZigBee, LoRAWAN and many proprietary SCADA and IIoT devices use 900 MHz," says Shade. "Lower frequencies can go a couple of miles and penetrate obstructions better, but in most cases, their data rates aren't as high as technologies that use higher frequencies. Cellular provides distance and speed, but it's more costly, while satellite is a lot more costly. This is why users have be aware of wireless capabilities, so they can choose what they actually need."
Seeking validation
In a wireless project's third stage, Phoenix Contact's Shade agrees that site validation must follow installation to make certain its components are located, configured, programmed and operating according to plan. Plus, it's important to verify that the facility's wireless spectrum is the same as it was in the original assessment, or determine if any new structures, equipment or other activities are going on, and respond to them if needed.
"It's always possible to follow up with another evaluation later, and keep trying to understand what's happening in a location where wireless is running," explains Shade. "We may understand a facility, but a new steel column may get added, or vehicles like AGVs may now be working there. We also need to know the impacts if communications are lost. Wireless assessments cost more up front, but they prevent downtime and lost production in the future by identifying issues before they become bad surprises later."
