In 2007, our world changed. Apple introduced the first iPhone, and our society, culture, entertainment and interpersonal relationships have never been the same. Wireless connectivity brought us new applications, new businesses, new services and is responsible for the growth of our on-demand world – “we want it now, so we should have it now.”
Manufacturing, ever wary and risk-averse, have been slower to adopt wireless technology. Performance issues in older wireless systems, along with how cumbersome and difficult it can be to install, inhibited its growth for a long time. Manufacturers were confident in their wires and the EtherNet/IP, PROFINET IO or Modbus TCP systems that ran on them. Only in rotating machinery, where wires couldn’t easily be used, did wireless gain a foothold.
That’s all about to change. According to several surveys, almost half of U.S. manufacturers are planning major wireless technology initiatives, many of them have already have deployed small wireless initiatives over the years that have proven viable.
There are four kinds of wireless systems that are typically being deployed in factories:
Wireless Ethernet – These systems simply move standard Ethernet around in much the same way that wired Ethernet does. Any communication protocol, including all the protocols of TCP/IP stacks, can be transmitted over a wireless Ethernet system.
Wireless Mesh – These systems (based on IEEE 802.15.4 standards) are designed to function well in large areas with obstructions that can impede a wireless signal. The mesh topology is designed to find a path around the obstructions. Derivations of the 802.15.4 standard (Zigbee, ISA100, and others) define the upper layer operations of these wireless mesh networks.
Cellular – Cellular systems use the same system as our mobile phones. Cellular systems are used when you have nodes distributed over a wide geographic range such as wells, pumping stations or tank farms. Data costs for cellular continue to drop, making these systems more viable.
Personal area networks (PAN) – PAN networks have been used for several years now to connect printers, labelers and identity devices. Many of these systems, like Bluetooth, are being extended to sensors. There is a lot of development going on in the wireless sensor area. These systems include pressure, temperature and vibration measurement.
Advantages to wireless include, of course, the ability to monitor and communicate with devices that are moving around the factory. Wireless systems are common on fork trucks and are carried by people moving around the factory scanning barcodes.
Some of the disadvantages of wireless technology are:
• Infrastructure and deployment costs are sometimes high. Site surveys are generally required, and much more up-front analysis is needed for a wireless system. This offsets some of the savings from not having to purchase or install wire.
• There is an additional cost for monitoring the network. A wireless network is not an install-and-done kind of network. It often requires more management from higher-skilled professionals than a wired system.
• Security is more of an issue with wireless. In a wired system, you know exactly where your wires are, but you don’t really know where your wireless signal goes. And you don’t always know what unapproved extensions people might make to a wireless system as off-the-shelf equipment is available that anyone can install to extend an existing network.
Despite these difficulties, wireless systems will continue to be deployed and grow in the future, especially once 5G begins to roll out.