Industrial Networks

No one's an island, and it seems that little automation remains unconnected through I/O devices, wire, cable, and network infrastructure. Increasingly, logic, sensors, and actuators communicate via Ethernet TCP/IP; other Ethernet protocols also are used. Traditional communications, serial networks, and 4-20 mA remain strong.

07/01/2006


 

AT A GLANCE

 

  • More Ethernet protocols

  • Serial, 4-20 mA strong

  • Network families

  • I/O connections

No one's an island, and it seems that little automation remains unconnected through I/O devices, wire, cable, and network infrastructure. Increasingly, logic, sensors, and actuators communicate via Ethernet TCP/IP; other Ethernet protocols also are used. Traditional communications, serial networks, and 4-20 mA remain strong. These are among findings from a recent Control Engineering and Reed Corporate Research on CE subscribers' use of and plans for industrial networks and communications.

Survey results were taken from those involved in specifying, recommending, and/ or buying industrial network products; among those, 51% do for in-plant requirements, 31% for OEM (resale), and 18% for both.

Among respondents, 34% have not formed or used cross-functional teams for industrial networks; 66% had. Of those who had, the following were represented: 61% engineering, 35% information technology, 26% plant engineering, 24% plant management, 12% customer service and tech support, 11% quality control and assurance. Purchasing, senior management, and suppliers were in the single digits.

The leading application for industrial networks is supervisory control and data acquisition (SCADA); followed by diagnostics, testing, maintenance; both continuous and batch processing; motion control, robotic equipment; and machine control, CNC equipment (graphic). Next applications include pump, fan, blower applications; continuous processing; packaging machines; materials handling equipment (elevators, cranes, hoists); and discrete product manufacturing.

Logically connected

Survey respondents indicated what devices in their applications were networked. Most connected were programmable logic controllers (PLC) hardware and network hardware devices (hubs, switches, routers, etc.). Network software tools, I/ O products and systems, and distributed and/ or hybrid control systems round out the top five (graphic). Sensors and related systems and transmitters took the next seven positions in rank, covering flow, motion, temperature, level, vision, proximity, and pressure.

For all equipment mentioned above, 10% to 19% of respondents said devices were not connected, but expect them to be connected within 12 months. Those devices most likely (18% or 19%) to be connected in the next year were: vision system hardware components; flow sensors and/ or transmitters; temperature sensors and/ or transmitters; and pressure sensors and/ or transmitters.

Leading networks, growth

Most common means of communication were Ethernet TCP/IP, RS-232, and 4-20 mA. See graphic for the rest of the top 10. Amazingly, 16 other networks or means of communications ranked in the double digits for usage. A notable trend is use of families of protocols: Modbus, Modbus TCP, and Modbus PWS; DeviceNet, ControlNet, and EtherNet/IP; Profibus-DP, Profibus-PA, Profibus-FMS, Profinet, and AS-interface; and F OUNDATION fieldbus (H1) and HSE (High Speed Ethernet).

Networks & Communication

I/O Modules

Percentage of wireless technologies were 34% for WiFi (IEEE 802.11b); 21% radio frequency identification (RFID); 14% Bluetooth (IEEE 802.15), and 6% ZigBee (802.11g).

Those who do not now use a particular network but plan to in the next year were in the double digits for RFID at 15%, followed by DeviceNet, then WiFi, ControlNet, Bluetooth, ZigBee, Modbus TCP, and CANopen. Those who plan to use (but don't now) at 8% or 9% include AS-interface, Ethernet Powerlink, Firewire, F OUNDATION fieldbus (H1), Profibus-DP, and Safetybus. All other networks, except WorldFIP, showed growth.

'We continue to see demand for Ethernet increase by over 50% compared to the previous years,' affirms Larry Komarek, automation product manager for Phoenix Contact's Americas business unit. 'Dropping costs and higher functionality of Ethernet infrastructure components, coupled with users emerging from successful trial stages, are contributing to the growth. Modbus TCP remains the dominant protocol, but EtherNet/IP is quickly growing in North America, while Profinet is showing strong growth in Europe.'

Booming demand for industrial networks, says David Harris, product manager, Logic Control Products, Eaton Corp., creates more market choice for users. Eaton sees a distinct preference for Ethernet-based networks like ModbusTCP and EtherNet/IP, as well as Ethernet TCP/IP for configuration and monitoring. These are 'easy to understand, simple to implement, and cost-effective using common materials, which means a shorter learning curve and a quicker return on investment. Moving to an Ethernet-based network also allows for more open connectivity to other devices through the use of enabling products like OPC servers.'

Eaton also sees strong support for 'serial networks, like Modbus,' Harris says, 'where small scale applications with the lowest cost of network implementation or legacy device support is needed.'

Far and away, reliability at 85% was the most important feature when purchasing industrial network products, followed by product quality at 72% and communication capabilities at 69%.

Other important features (60% or higher) were networking capabilities, quality of documentation, ease of use, and environmental ruggedness. Showing an unfortunate short-term focus, price was at 47% and life-cycle costs at 37%.

How to select a vendor

Wireless

Respondents rate getting help among the highest (very important or important) attributes when selecting a manufacturer to purchase industrial network products. At 98% or higher were: Responsiveness to problems, customer service, and technical assistance. 'Ease of doing business' and reputation tied at 96%. Knowledgeable sales persons and application assistance were 94% and 93%. Above 85% were completeness of product line, available training, and previous experience.

Difference between very important and important was large with some criteria. For instance, 'leading brand' garnered 8% very important and 58% important for a net of 66%.

Highest among product types purchased were I/ O devices and connectors at 97%, wire and cable 96%, network infrastructure (bridges, switched, routers, etc.) 92%, and network-enabled controllers 86%. Network software was 77%, network-enabled sensors 67%, and network-enabled final control elements (actuators) 61%.

Nearly 60% of respondents track return on investment. For those, typical payback for annual expenditures on networking investments was 12 to 15 months.

See survey results for details at resource.controleng.com under 'Research.'

Industrial network products

For more manufacturers, visit www.controleng.com/buyersguide . For systems integrators, visit www.controleng.com/integrators . Also visit company Websites listed.

Ethernet processor for PLC

Users of Allen-Bradley PLC-5 controllers boost network throughput and expand data collection and messaging with PLC-5 Series F Ethernet processor from Rockwell Automation. Ethernet protocols have infiltrated the plant floor with remote monitoring and management, IT integration, and new services like voice and video. For EtherNet/IP protocol, Series F builds on previous processor designs and can auto-negotiate between 10 and 100 Mbps. An RJ45 connector on the faceplate connects to CAT-5 Ethernet cabling without an external transceiver. An upgrade to Rockwell Software RSLogix 5 programming software (version 7.1 or later) is needed to manually negotiate data speeds or use new e-mail messaging based on event and machine occurrences. (No software update is needed for higher Ethernet communication speeds using auto-negotiate.) A 'Step Forward' program ( www.ab.com/stepforward/plcupgrade.html ) can be used to exchange field units for the new processors. www.rockwellautomation.com Rockwell Automation

PLC/DCS cables

More than 20 automation manufacturers and at least as many industrial networks are listed in the 'PLC/DCS Cable Cross Reference Guide,' one of several references at the 'Cable College' area of Belden CDT Electronics Div. Website. A three-page table lists manufacturers, system names, and Belden part numbers. The fourth page is a protocol cross-reference, matching industrial networks to part numbers for many Belden wires and cables. www.belden.com Belden CDT Electronics Div.

Physical security for Ethernet switches

Controllers

Phoenix Contact expanded its standard function (SF) unmanaged switch line. The 13 new SFN (narrow) switches use third-generation switch technology to lower installed costs by 20-70% compared with current offerings. SFN 5-and 8-port switches (10/100 Mbps) provide low-cost, industrially hardened, entry-level switch functions in a narrow housing width, and 100 Mbps glass-fiber configurations. The line supports one or two ports with SC or ST-style connectors. Each SFN switch can add optional security frames to block unused RJ45 ports and lock existing cables. This 'physical layer 1' security restricts network access by unauthorized personnel and is easy to implement. In fall 2006, the series will include the first industrial unmanaged IEEE 802.3z Gigabit switches for future-proof and data-intensive applications. www.phoenixcon.com Phoenix Contact

Unmanaged Ethernet switches take more heat

Ethernet

Schneider Electric expanded its line of open, industrially tough Telemecanique Connexium network components, with the Connexium IP67 Ethernet switch, unmanaged Ethernet switches with expanded temperature ratings, and Ethernet gateway. Features focus on boosting ease of use and reliability. IP67-rated switches can be installed on plant floor or machines, withstanding water spray and other conditions in outdoor applications. Built-in store-and-forward technology checks messages for proper length and CRC (cyclical redundancy check), ensuring the correct messages are always forwarded, increasing reliability and reducing traffic. Unmanaged Ethernet switches operate from -40 to 70 °C and offer copper/fiber options, Auto-MDI, alarm relay, and redundant power source inputs. TSXETG100 Ethernet gateway connects from Modbus serial devices to Ethernet and sets up through a browser. www.us.telemecanique.com Schneider Electric

4-wire D-Coded Ethernet cables, switches

Security

Turck Inc. announced a line of 4-wire D-coded Ethernet physical media products, including cables, switches, and conduit adapters compliant with EtherNet/IP. Cordset configurations include pre-molded M12 eurofast connectors, receptacles, and RJ45 plugs. Tough PVC cable jackets meet TIA/EIA568-B.2 Category 5e performance requirements for 10 and 100 Base-T Ethernet and are UL-rated for sunlight and oil resistance. Industrial switches provide 5 or 9 eurofast ports with a 4 or 5-pin 7/8-16UN minifast power port and NEMA 1, 3, 4, 12, 13, and IEC IP67 protection. Switches automatically sense transmission speed and store addresses in the routing table. Transition products include conduit adapters that allow one or two-port eurofast drops from standard conduit bodies, and a cabinet adapter for transition from eurofast to RJ45 connectors. Gasket and mounting hardware are included. www.turck.com Turck

EtherNet/IP intelligent modules

Safety (Machine and process)

Cutler-Hammer Intelligent Technologies EtherNet/IP (D77D-EIP) from Eaton's electrical business increases the functionality of connected products, allowing monitoring and control for I/O devices, motor control, and other related devices, concentrating all data into one node. EtherNet/IP Adapter is a slave device on EtherNet/IP and a master on QCPort. D77D-EIP has an auto-configure button for default operation, automatically configuring the EtherNet/IP assemblies to the QCPort system devices. www.eatonelectrical.com

Industrial wireless WAN router

Networks & Communication

Digi International introduced the Digi Connect WAN IA, a new wireless wide area network (WAN) cellular router and gateway with features for industrial automation applications. It provides secure cellular GSM or CDMA connections for reliable primary and backup network connectivity to industrial automation devices, such as SCADA devices, programmable logic controllers (PLCs) and remote terminal units (RTUs). Wireless can be more cost effective than traditional landline connections, provide broader coverage to remote locations, and avoid wire-related vulnerabilities like outages from weather or construction, Digi says. It connects Ethernet to cellular or serial to cellular interface and features industrial hardware/software components including a terminal block for power, DIN rail mounting, Class 1, Div. 2 certification, and Modbus protocol support. www.digi.com Digi International

Industrial gigabit Ethernet switch

I/O Modules

Moxa Technologies Inc. expects to launch a new gigabit Ethernet switch for industrial Ethernet applications. EDS-518A new generation Ethernet switch meets the European Union's RoHS standards. Scheduled for release later in 2006, it is a standalone 18-port managed Ethernet switch with 2 combo gigabit ports, built-in RJ45 or SFP ports for gigabit optic communication, and gigabit Ethernet Redundant Turbo Ring (recovery time &300 ms) to increase network backbone reliability and speed. It supports multiple intelligent network management functions. www.moxa.com/usa Moxa Technologies

AS-Interface gets new I/O system

Wireless

Wago family of AS-Interface products for the Wago-I/O-System includes an AS-interface Master (with support for 'Safety at Work' devices), machine mount (IP67) I/O modules, in-cabinet mount (IP20) I/O connections, and an AS-Interface power supply. 'AS-Interface is perhaps the simplest fieldbus network available for wiring of actuators and sensors, with wiring savings up to 40%,' said Mark DeCramer, product manager Wago-I/O-System. It uses one cable to connect I/O modules; little knowledge of bus systems or communication protocols is needed to start, he says. Master module fits within the node and is less than 0.5-in. (wide). At a minimum, a node requires a master module, bus coupler (programmable or non-programmable), and an end module. It can be outfitted with more than 200 Wago analog, digital, and special function modules to easily connect to Ethernet, DeviceNet, Profibus, CANopen, and I/O types not traditionally support by AS-i, such as stepper control, serial, and up/down counters. Slave I/O nodes connect to the master module and include IP67 machine mount and IP20 in-cabinet (DIN-rail) mount designs. Five configurations are available. www.wago.us/as-interface.htm Wago

 

 


Online Extra

Related Control Engineering articles include:

Benefits of Intelligent Safety Networks
For General Motors, the benefits of using ISNs are profound. It is expected to cut the company’s wiring costs by half while reducing the number of operators involved in safety operations by 75%. Area safety operations in a manufacturing plant can be scaled down to one or two operators who activate emergency switches that are run by the network, thus improving cost efficiency.

GM’s example shows how separate controller and safety network architectures are becoming obsolete, thanks to the emergence of dual-purpose safety controllers that handle both monitoring and control of safety and non-safety functions with a single CPU. Intelligent safety networks are now available for motion control products without requiring external hardware.

ISN technology lets operators perform essential tasks such as inspecting, aligning, cleaning, and changing out worn tools that previously could only be performed when electrical power was completely cut off from drive mechanisms. By allowing safe access to machinery with power still available, ISNs facilitate faster restarts, machine accuracy (due to elimination of repositioning), reduced brake wear, and shorter machine downtime. As a result, overall machine efficiency can be improved—sometimes dramatically.

Documenting compliance with accepted industry safety practices becomes easier with ISNs, since electronic records are maintained by the system. Also, effective safety systems that allow easier access to machines by operators make it less likely that controls will be overridden by frustrated operators. ISNs help cut downtime by allowing operators to quickly troubleshoot machine stoppages—especially nuisance trips—and get production lines back up faster than with traditional hardwired safety systems.





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