Industrial wireless technology has provided plant managers and operators with a competitive edge as they search for new and innovative ways to improve the standard of communication among their distribution and production units.
An effective infrastructure for communication is all it takes to make it feasible for industrial equipment to deliver the highest levels of availability, maintainability, and reliability, and this reduces their operation and support costs which in turn minimizes capital investments.
But a lot of managers and plant operators remain hesitant to deploy such technology at facilities. Apart from this, facilities that have already adopted wireless technology may not have realized the potential of this technology or the benefits they could derive from it.
Let's look at eight ways in which industrial wireless network users can identify and even fix problems in their infrastructure:
In regular WiFi communication, WiFi radios are configured with the same settings and operate in the same area through the same medium. So you should consider all radio devices while evaluating a channel's utilization. For example, if you are checking the 2.4 GHz channel for frequency saturation, you should consider all access points that use the channel and devices that don't use 802.11 communications such as Bluetooth, ZigBee, and microwaves (no, this has nothing to do with warming up your pizza!).
Another challenge is 2.4 GHz has just three non-overlapping channels. If they are saturated, you should switch to a less crowded channel. The 2.4 GHz frequency can become crowded and isn't recommended when it comes to industrial applications.
But 5-GHz frequencies provide a number of channels and have additional non-overlapping channels. Most countries need wireless devices to support DFS so they can operate legally in this frequency. But, in industrial environments, deploying devices with 5-GHz radio and DFS functions lets you choose the cleanest form of communication and give you the best communication quality.
Scientific distance calculation
A high 802.11 transmission rate needs strong signals. Insufficient radio strength will result in a low throughput or even disconnection. There are a number of ways in which you can improve signal reach, such as installing high gain antennas or switching to lower frequencies like 900 MHz to reduce the effects of path loss in free space.
Using wireless distance calculators can help you with theoretical models of the area that can be confirmed by physical surveys of sites. So you should plan long-distance parameters for the network using distance calculators and verify results through actual surveys to gain additional control of bandwidth and capacity.
Wireless redundancy technology
Even with clean communication environments and sufficient reach, there are other factors that can cause instability in wireless networks. Issues with the setup like hidden nodes could lead to problems in the connection of even the best-designed network.
Also, when deployment locations aren't controlled, unexpected interference from unknown sources may affect networks. Wireless redundancy technologies like RF redundancy, Aerolink, or RSTP helps you recover from unexpected failures especially when it comes to critical applications. This will help ensure maximum uptime.
Sufficient AP coverage
Wireless AP's come with limited coverage. If you want wireless clients to smoothly roam between them, you will need a coverage overlap. Site planning software AirMagnet or Ekahau works here. They can simulate wireless coverage heat maps for visualizing AP distribution in a network and planning the location of APs. Wireless coverage can even be extended by altering antennas, but the vertical coverage of antennas is usually overlooked by users. Most 802.11 antennas are passive and don't amplify signal strength.
The only way of doing so is by compressing the radiation pattern from the antenna signal. Omnidirectional antennas have 360-degree horizontal radiation angles. To improve horizontal coverage, you will have to sacrifice vertical angles. So, if you switch to high-gain antennas, don't place them too high. If they are too high, the signal strength won't be able to reach devices at ground level.
MIMO client antennas
Both 2.4 and 5 GHz wireless communication need a clear LoS (Line of Sight) between the AP and clients. You can maintain wireless connections with the help of obstacle-reflection and signal penetration techniques, but strength reduction will still affect stability and throughput for your network. One of the easiest ways of avoiding connection sheltering is to increase AP distribution, which could end up being very expensive.
By using 802.11n 2x2 MIMO, you can install dual antennas on mobile devices and increase their wireless coverage.
You will have to deploy advanced wireless roaming technology in order to achieve millisecond-level break time. Even if there are standards like 802.11r, which can optimize roaming performance, most M2M vendors rely on roaming technology.
Advanced technologies enable wireless clients to search automatically for new AP's when the current connection's weak. Configuring correct threshold parameters are essential to avoid downtime. Adopting roaming technology that lets operators tweak roaming parameters depending on different environments and scenarios will help eliminate downtime and optimize performance.
Protocol compatibility issues
Some characteristics of 802.11 protocols do not allow transparent communication between wired Ethernet and wireless links. Even though most TCP/IP based automation protocols can transmit data, there are situations when 802.11 functionality has to be tweaked to make it compatible with industrial automation protocols.
When wireless clients aren't the endpoints but are devices that are used for connecting additional Ethernet-based endpoints, 802.11 protocols won't be able to forward data packets properly using the MAC address. Moxa solves this limitation with its MAC clone technology.
Smart handheld devices such as smartphones and tablets are used in a lot of industrial operations. A number of smart device vendors including HTC, Apple, Sony, and Samsung sell such devices with different operating systems. One thing they have in common is they can communicate using the 802.11 standards very well.
Only devices that conform to certain interoperability standards can carry this logo. It is issued by the Wi-Fi Alliance – no, this has nothing to do with Star Trek! Not all IEEE 802.11 compliant devices are submitted for certification to the Wi-Fi Alliance since the costs are high. Moreover, the lack of this logo doesn't imply devices are incompatible with Wi-Fi devices.
The big picture
WiFi technology is growing at a tremendous rate, and for almost every problem there is often more than one direction to go. If you are facing network or connectivity or speed issues, then you must try one of these solutions to see if it makes any difference. A faster network connection will translate into increased productivity and better results. A slower connection on the other hand leads to frustration and subsequently poorer results.
Photo credits: Pixabay