Wireless Infrastructure Considerations for Your Shop Floor

Wireless technologies have matured considerably over the last decade and have proven very useful in the workplace. They remove the need to be tethered to a specific location and allow users the ability to wander around the manufacturing shop floor while keeping access to critical information close at hand or provide connectivity to remote locations that may have been inaccessible through traditional means. With the obvious benefits of using a wireless infrastructure, why continue using wired hardware?

Wireless networks within a business environment require careful planning and execution in order to achieve optimal results. While some constraints are similar to wired networks (distance, electromagnetic interference, capacity), there are other concerns that must be addressed (wireless coverage, security, frequency band utilization, roaming and wireless standards utilized). I cannot stress enough the importance in researching the products being considered and talking with the manufacturers or support teams regarding the application of the products. Areas for consideration include:

Size of Installation – Physical Area: It is critical to determine the area of coverage required and make sure that the technology being utilized is capable of servicing the needed area. All standards outline approximate indoor and outdoor range expectancy. In all cases, any solid objects interfering with the line of sight between the wireless devices and the access point will decrease the signal strength and reduce range. In addition, higher frequency bands do not travel through objects as well, reducing their effective range further. Coverage can be extended through the use of multiple access points. This creates other considerations that need to be addressed. How well do the chosen access points work together? Can one pick up the load if the other drops off for some reason? Is roaming between the multiple access points expected? If so, is the proper hardware in place to support this capability and do the devices connecting to the “mesh” network support hopping from one access point to another?

Size of Installation – Number of Devices: Just as a physically wired switch has a specific number of connections that it can support, there is a limit on the number of wireless devices that a wireless access point can support. Even though a manufacturer might claim that its access point can handle 127 or 255 devices, what kind of performance might one expect from an access point loaded to its limit? The access point has to process every inbound and outbound packet of data requiring a significant amount of compute power to facilitate. Enterprise-grade equipment is usually very capable, but be wary of consumer level brands indicating that level of connectivity. It may be possible to connect 127 devices to that off-the-shelf Linksys purchased at the local computer shop, just don’t expect bandwidth anywhere near the stated standard. Multiple access points can help alleviate this situation, but yet again other issues need to be addressed with multiple devices broadcasting.

Environment: Wireless networks are becoming more robust and prolific. As a result, the wireless bands are also becoming more crowded, causing the requirement to move into high frequencies (shorter wavelengths). While this does provide room for increased growth and bandwidth, it does necessitate examination of the application. The current 802.11n standard allows use of both the 2.4GHz and 5GHz band. A new standard being promoted, 802.11ad, opens up the 60GHz band for use. As noted above, higher frequencies are more susceptible to physical obstacles and can be more susceptible to electromagnetic interference. Being aware of the frequencies in use will help determine what technology to use and how it is deployed. Think of an industrial plant floor with heavy machinery, lighting and power units that contain electric motors, ballast, power supplies and transformers. Understanding how these items generate electromagnetic interference (periodic, continuous, sporadic) and the strength of the electromagnetic interference can help determine if a wireless solution might be feasible.

Security: An ongoing issue with anything put into the air is who else has access to the data. With all the different levels of security available for wireless networks, the ability for someone to eavesdrop on the information is always a possibility. Understanding the type of data being broadcast and the sensitivity of that data needs to be carefully considered.

These are just a few items to look at when considering any type of wireless environment. The critical point is knowing the desired goal, understanding requirements and constraints in getting there and properly evaluating the options for the best path. I am going to reiterate: Communication with the product suppliers and support staff can help alleviate many frustrations and surprises.