Ethernet is continuing to broaden its reach, letting plant managers link more and more equipment to Ethernet backbones. The benefits of using a single networking architecture, coupled with the low cost of Ethernet connectivity, are making it more viable to use the bus for many different types of equipment.
As vendors and customers become more comfortable with Ethernet, many are deciding that the benefits of using it to connect more equipment to a central network outweigh the minor cost savings that can come with alternative networking solutions. Ethernet compatibility, therefore, is being added to more peripherals, and more of them connecting without wires.
In some extremely remote environments, cellular connections are serving as the wireless link. Now that the business network has become the dominant architecture in most factories, its expansion to all corners of the plant floor is continuing almost unabated.
“There’s a huge trend to add more equipment using Ethernet. You can mix and match all types of telephony equipment and cameras that can all co-exist on the same network,” says Mike Hannah, product development manager, Ethernet & Infrastructure for Rockwell Automation (www.rockwellautomation.com). “That said, many people don’t understand the full value of going to Ethernet, except maybe when they add inspection cameras or cameras used for safety and security.”
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As more plant managers see the benefits of using Ethernet’s transmission control protocol/Internet protocol (TCP/IP) technology for communications throughout their facilities, network architectures are changing. As more machines share more data, managers gain more insight into areas that were once considered islands of automation. At the same time, these managers find that they must design networks that are capable of handling higher volumes of data.
“We’re seeing a conversion to true integration of managerial networks and shop floor networks. They operate as one, not as islands,” says Jim Toepper, product marketing manager for Ethernet switch maker Moxa Americas (www.moxa.com). “That requires a lot of bandwidth. When you’ve got video inspection, data logging and PLCs (programmable logic controllers), you’re generating a lot of data. Some PLCs broadcast a lot of data, which takes a lot of bandwidth.”
Most feel that any investment that helps them gain more bandwidth often pays for itself by improving productivity. With data coming in ranging from the front office to incoming deliveries to the health of key production equipment, managers can ensure that plants are running more efficiently.
“What people realize is that what limits them is visibility down to the plant floor,” Hannah says. “With Ethernet, engineers can sit in the control room and see if all the equipment is running and whether they have materials for it so they’re not starving the machine.”
Flattening the architecture
Having a single architecture is the central requirement for improving efficiency, making more information readily available to all authorized users on the network. As Ethernet’s role in industrial applications has expanded, designers in many areas have worked to make data sent on alternative networks more accessible.
That’s very important with many peripherals. It may not be cost effective to replace some non-Ethernet equipment, and other products may not be available with the ubiquitous interface. That’s where protocol converters come in handy.
Though many pieces of equipment are not yet available in Ethernet-compatible versions, managers can still gain many of the benefits of connectivity by using serial –to-Ethernet converters. For example, many computer numeric control (CNC) machines are currently connected to computers via serial cables, so humans usually have to go down to the factory floor to make adjustments. When they’re linked to a serial to Ethernet box, many steps can be automated.
“A multiport serial-to-Ethernet device can network all your CNC machines on the floor to your existing network,” says Leo Lee, product manager at Ethernet peripherals maker Neteon Technologies (www.neteon.net). Your engineer can continue working in the office and then upload the schematic directly to the network and into the CNC. They no longer have to transfer the schematics physically to the computer.
He adds that the latest serial-to-Ethernet devices are more robust, offering features such as surge protection and low power consumption. Many observers note that as more equipment is connected via Ethernet, bandwidth requirements are rising rapidly. That’s prompting a transition to faster versions of Ethernet.
“PLCs, HMIs (human-machine interfaces), security systems and plenty of other devices are now on the network. That definitely wasn’t the case just a few years ago,” Toepper says. “We’re starting to see, for the first time ever, people going to 10 Gbit Ethernet. They wouldn’t need that type of bandwidth if there weren’t a lot of devices on the network.”
Toepper also notes that as speeds get higher, Ethernet’s ability to perform complex tasks like motion control is expanding. The emergence of the IEEE 1588 standard, promulgated by the Institute of Electrical and Electronic Engineers, gives managers the ability to synchronize several products using a standard that integrates with Ethernet technology.
“The ability to run complex systems using standard Ethernet is improving,” Toepper says. “It used to be that the only way to do real time or synchronize systems was with proprietary technologies. But with IEEE 1588, you can synchronize down to the nanosecond level.”
Keeping track of data
As more equipment feeds data into the industrial Ethernet architecture, many companies are beginning to store industrial data on the plant floor. That’s becoming a necessity as manufacturers need to maintain very detailed documentation for every component they produce. Even suppliers in non-regulated fields are finding that they need to maintain every aspect of every lot’s production parameters on a storage server.
“We recommend that data be stored in the factory,” Rockwell Automation’s Hannah says. “Companies that need to track quality data for a recall need to know exactly where lot runs were produced.”
Whether they’re looking for historical data or checking the latest inventory stats for a given machine, today’s managers want to have immediate access to information. Even more importantly, all the machines on the network need to get messages on time without any interruptions. This focus on nonstop computing and connectivity means a few dollars spent on backup hardware can pay big benefits.
“As more of the facility runs on Ethernet, you need to put in more firewalls and routing technologies, and more people are utilizing redundancy,” Moxa’s Toepper says. “You need redundancy when you’re doing something like video inspection, you can’t have network failures that causes inspections to stop.”
Another aspect of retaining connectivity is to provide good debugging tools. The shift to Ethernet gives plant managers access to a plethora of effective tools. However, technicians are finding that it can be simpler to diagnose networks and equipment by plugging into USB ports than by connecting with an Ethernet cable.
“USB is used for temporary connections, like hooking up a PC for troubleshooting or downloading a program,” Hannah says. “If you plug a PC into an Ethernet port, you need the right IP address. When you plug into a USB port, you don’t need that setup.”
>> Click here to read about the rapidly growing acceptance of wireless peripherals.
