Ethernet on the plant floor: 6 key considerations for success
Already ubiquitous in enterprise office environments, Ethernet is now making its way to the plant floor, and with good reason. Using Ethernet in both environments makes it simpler to provide plant-wide connectivity and to pass data between the plant floor and IT or business departments. Data can be made available anywhere and everywhere it's needed – from supervisors in the plant to busin...
Already ubiquitous in enterprise office environments, Ethernet is now making its way to the plant floor, and with good reason. Using Ethernet in both environments makes it simpler to provide plant-wide connectivity and to pass data between the plant floor and IT or business departments. Data can be made available anywhere and everywhere it's needed %%MDASSML%% from supervisors in the plant to business line managers, maintenance staff and purchasing managers.
To help you make a choice that will serve you well for the long haul, we offer these six considerations for choosing an industrial Ethernet solution that can withstand the rigors of the plant floor.
1. Go for durability, simplicity and flexibility . Office Ethernet equipment that is meant to be used in a clean, temperature-controlled environment won't translate to the plant floor. You'll need shielded cables, metal connectors and switches that can withstand higher temperature and vibration specifications. Additionally, the typical office Ethernet is configured in a large star topology, whereas a plant floor topology may be a star, ring, tree or a line, depending on the plant and machine configuration.
Whereas office Ethernet switches typically get care and feeding from the IT department, plant engineers will likely take on the chore on the plant floor. They need devices that are quick and easy to set up and replace should the need arise. Given that, Web-based setup tools are a must.
2. Consider the protocol . By itself, IEEE 802.3 Ethernet merely defines how to construct packets for transport over a certain type of wire. On top of that, you need a protocol that addresses the specific requirements of reliable, high-speed machine-to-machine communications.
On the plant floor, machines are in relatively close proximity to one another, obviating the need for a protocol that can find a computer located half-way around the world.
Meeting these requirements requires a specialized protocol, one that results in packet turnaround times more than 10 times faster than TCP/IP. Additionally, industrial Ethernet protocols foster highly reliable communications, with an assurance that packets get to their destination the first time in a predictable timeframe %%MDASSML%% two attributes that TCP/IP can't match.
3. Configuration should be simple . As noted earlier, industrial Ethernet equipment is often cared for by control engineers, not the IT department. Whereas IT folks may relish a command line interface that gives them highly granular control over their switches, control engineers want a far simper approach. Industrial Ethernet switches should come with a GUI-based tool that makes them simple to configure and operate.
4. Consider all present and future requirements . You have varied requirements on the plant floor, including peer to-peer communications, distributed I/O, machine safety, motion control and data acquisition. Your industrial Ethernet solution should enable you to support all of them by adhering to industry standards. And while you may not need all of these functions today, perhaps you will tomorrow %%MDASSML%% it's best to be prepared.
At the same time, you may want to integrate production data with some of your business systems such as enterprise resource planning applications. And it's useful to be able to carry traffic from traditional office applications such as e-mail over the same wire, even if they use the traditional TCP/IP protocol. Your industrial Ethernet network should be flexible enough to allow all of these scenarios, while at all times ensuring that critical machine floor traffic gets the bandwidth and throughput it requires.
5. Make sure it plays well with others . Another advantage of a standards-based approach to industrial Ethernet is that it enables your solution to communicate with the various legacy networks and machines that may populate your plant. A solution that employs industry standards such as XML, for example, makes it possible to represent an entire machine as a component that is independent of its underlying control system.
Such a capability, when combined with a graphical configuration tool, enables you to simply draw lines between your desired input and output machines to establish connectivity, no matter what native protocol each machine may employ.
6. Consider operational costs . Calculating the cost of an industrial Ethernet solution goes far beyond the initial equipment tab to include installation, engineering and long-term operation and maintenance. To keep these costs manageable, you need a solution that includes not only the simple-to-use GUI-based configuration tools, but effective management and diagnostic capabilities.
Again, you should look for tools that employ standards such as OPC, a specification that defines how to communicate real-time plant data between control devices from different manufacturers, and SNMP, an industry standard network management protocol.
While many factors will play into your choice of an industrial Ethernet solution, following these guidelines should help ensure that your choice will be one that will keep your plant functioning at peak efficiency today and into the future.
Jeremy Bryant is an industrial communications marketing manager at Siemens Energy & Automation Inc. in Norcross, GA.