The use of Ethernet technologies is penetrating almost every application in industrial automation. The generalized Ethernet communication connection allows the transfer of data through cables composed of multiple twisted wires, similar to a home network. EtherNet/IP is a communication protocol that uses the framework of standard Ethernet data transfer to communicate specific information for manufacturing applications. EtherNet/IP is the industrial Ethernet protocol supported by the Open Device Vendor Association (ODVA), and is becoming the standard of many organizations for full plant data communication.
Many industrial facilities rely on Programmable Logic Controllers (PLCs) to conduct the majority of the automation activities. Ever since its introduction in the 1960s, PLCs have revolutionized the capabilities and space of all applications. All industries including Plastics, Food & Beverage, Infrastructure, Oil & Gas, Pharmaceuticals, and Electronics rely on the common notion of signal transfer from one source to another. In the past, most industrial plants relied on either 4-20 mA or frequency outputs to transmit instrument control. Although this practice has been proven functional, the simplicity of one way signal is a major downfall. Ethernet networks, on the other hand, provide industries with the ability and tools to overcome complex process control and monitoring obstacles. Material flow metering, variable frequency drives, high accuracy scales, and safety control modules, are just some of the tools currently used today that are trending and evolving into more diverse and user friendly models using EtherNet/IP communication.
All flow meters, be it orifice plate, magnetic, or coriolis, need to transmit data through an indicator to be useful. For example, an indicator can be configured to read flow rate, total liquid transferred, or instantaneous flow rate. Due to the limits of one-way 4-20mA signal output, many indicators were previously able to only report one of these readings. However, when indicators are equipped with an EtherNet/IP module, they are able to also report process flow information along with density and temperature of the fluid. Additionally, some meters can provide diagnostics which verifies that the meter is working accurately and within specification.
Variable frequency drives (VFDs) provide the ability to change the speed of a motor by varying the frequency and voltage of the supplied power. While some drives are limited in the number of different speeds they can output, EtherNet/IP embedded drives possess the ability to provide an infinite number of speeds on a common 0-60Hz frequency. All drives operate on a set of given parameters which may include metering, setup, frequency settings, diagnostics, faults, and process display. EtherNet/IP based VFDs allow most of these parameters to be accessed remotely over a network. Full load amps, torque values, energy usage, and reference speed, are valuable information which can be monitored thanks to the help of Ethernet communications.
Industrial scales rely on load cells to monitor weight. A load cell is a unique type of transducer that translates strained force into a measurable electrical output which is then translated into a meaningful measure of weight by an indicator. Many indicators serve as a main display of weight and provide the means for calibration and noise filtration. EtherNet/IP embedded scale indicators take a step further and provide the ability for remote monitoring, calibration, and setup of the indicator and scale. The finalized configuration file can then be transferred from one unit to another.
Another major advantage of EtherNet/IP devices is realized when it comes to installation. Previously, installations that would have required 10-15 wires can now be replaced with a single shielded cable from each device. Many manufacturers of Ethernet embedded equipment also provide the ability to save and export the configuration file which governs the function of a device. This configuration file can then be distributed to any identical unit. What this means to an industrial plant equipped with Ethernet embedded equipment is that the downtime accrued when a device fails is often drastically reduced.
It should be noted that standard continuous Cat5e Ethernet cable has an effective range of approximately 100 meters. Before a cable reaches this limit, the signal will need to be repeated by a switch. Adapters can also be added to a network to transfer information through a fiber optics connection and still use the EtherNet/IP protocol.
EtherNet/IP is one of the leading industrial Ethernet networks used globally. Look at any consumer product used today and chances are, an EtherNet/IP device was used to make it. Because of its many advantages, the use of EtherNet/IP will continue to expand the efficiency and potential of industrial automation.
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