Figure 1. Consumer/commercial Ethernet must reliably interconnect all types of industrial automation elements from the field, to the control room, and up to the cloud. (Image: AutomationDirect)

Since the standardization of Ethernet in the 1980s, progressive performance advances and economies of scale have made this the leading digital networking technology for commercial, consumer, and industrial applications. Although Ethernet in the factory has now been widely adopted, it lagged behind commercial implementations due to difficulties installing the media in harsh industrial environments, and in the early years, a lack of determinism required for critical applications.

Ethernet usability for discrete manufacturing factories, all sectors of the process industries, and other demanding applications has improved greatly because of developments surrounding ruggedized installation media and devices targeted for these markets. Automation designers now have more industrial-grade options than ever for specifying higher-performing Ethernet systems ( Figure 1).

Consumer and commercial networking were based on the need to connect many computers and related devices together, often transferring large amounts of data sporadically. Industrial networking evolved on a much more point-to-point or limited multi-drop basis, communicating small amounts of data, but rapidly and in a deterministic manner, often on a fixed time schedule.

Initially, serial communications (RS232/422/485) provided an adequate balance of speed, installation distance, and environmental robustness for industrial purposes. Collectively called “fieldbuses,” some versions used proprietary protocols, but later, an open standard called Modbus rose to prominence.

Figure 2. AutomationDirect offers the Stride family of ruggedized networking products in factory-friendly form factors and with industrial-specific features. (Image: AutomationDirect)

As users became comfortable with commercial Ethernet, they began to seek the same benefits in industrial installations. Early adopters used commercial-grade products for industrial applications with some success, but a number of advances have made Ethernet much more practical for communications from the plant floor, to the control room, and up to the enterprise via the cloud.

For Ethernet to become the preferred industrial and automation networking technology, a number of developments were needed:

  • Tough installation media: Industrial environments are full of harsh physical, environmental, and electrical noise conditions. Ruggedized installation media — such as shielded cables with tough high-flex jackets, protected RJ45 connectors and M12 quick disconnect (QD) fittings, and field-wireable connectors — make it possible to perform factory and machine cable installations up to the rated 100-m distance.

  • Industrialized devices: Industrial Ethernet devices are commonly rated for extended temperature ranges, and they can be powered by typical industrial 24VDC or vehicle 12VDC supplies. Additionally, other performance characteristics have now largely caught up with commercial counterparts (Figure 2). While 10/100 Mbps speeds are readily available, newer 1 Gbps speed is generally the new standard moving forward. Support for power over Ethernet (PoE) and PoE+ is a popular way to power field devices, saving installation cost.

  • Improved protocols: Designers can use operational technology (OT) protocols — such as EtherNet/IP, Modbus TCP, PROFINET, EtherCAT, and many more — in conjunction with information technology (IT) protocols like OPC UA and MQTT. The OT protocols provide reliable performance, while the IT protocols incorporate data contextualization and improved security.

A new implementation of Ethernet called Ethernet-APL (built upon the IEEE802.3cg standard) was recently developed to address remaining industrial installation challenges. Ethernet-APL enables cable installations of 1,000 m for trunks and 200 m for drops, supports 10 Mbps speeds (plenty fast for most typical field I/O devices), delivers increased power, and includes intrinsic safety options for hazardous locations.

While there may still be times when proprietary or serial communications are useful, the wide availability and low cost of high-performance industrial-specific devices and installation media are making industrial Ethernet the best approach for future-proofing applications and operating most efficiently.

This article was written by Bill Dehner, Technical Marketing Engineer, Automation-Direct (Cumming, GA). For more information, visit here  .