Protocol gateways make IoT efficient, accurate, and low cost
Having complete and current data about any process can result in better decision making. One of the primary benefits of the Internet of Things (IoT), sometimes called the Industrial Internet, is that companies can make improvements in production processes, end products, and logistics that reduce costs and energy usage. By capturing and centralizing information from all the pieces/parts of production and doing so in a timely, automatic, non-intrusive manner, analytics programs can find places for these improvements.
Whether it be a factory, a processing plant, or a remote stand-alone location such as a well site, a typical manufacturing operation contains a mixed bag of sensors, instruments, PLCs, drives, RFID/barcode readers, energy management systems, and other intelligent devices that don’t all communicate on the same network.
Over time, sensors and automation are purchased from multiple OEMs, who in turn purchase equipment from multiple vendors, and these purchases occur at different points in time and stages in the development of automation technology. Companies merge and move equipment between plants, and upgrades to equipment are made at staggered intervals for many reasons including funding, scheduling downtime, changes to the end product, or breakdowns and obsolescence of parts.
Additionally, more and more sensors are being added to equipment new and old so that more data can be gathered for analytics applications. For example, an engine oil sensor can provide information so that maintenance can be scheduled based on need and optimal performance instead of a “suggested maintenance interval.” Automation replaces manual processes to improve efficiency, and this allows more information to be easily tied into the data collection process.
Does all this “stuff” just natively communicate to each other or in the same “language?” Of course not! Different media (serial, Ethernet, wireless, and proprietary networks, for example) and even different protocols on the same media are common. Even as industrial control products have embraced open architectures and standards, there are still a lot of options available. Sensor and equipment vendors select which communication methods to support based on a variety of factors, including cost, complexity, and in some cases, a desire to protect intellectual property (IP). Different parts of the world embrace different standards.
So how can a manufacturer who wants to optimize their process get the data from the machines to a central database most effectively? Gateways are the answer.
A gateway, sometimes referred to as a protocol converter, is a device that can communicate on multiple networks, passing the information from one to another. Using a mix of gateways, it’s possible to connect all the diverse equipment in a facility to a common network, and from there to a data acquisition system and/or database. As shown in Figures 1, 2, and 5, gateways can transfer data over multiple communication media options.
Gateways can be dedicated hardware, or the function can be embedded in the firmware or software of an intelligent device such as a programmable logic controller (PLC), human-machine interface (HMI), or computer. Examples are shown in Figure 2.
Embedded into most gateway products are the hardware interface and low-level protocol details of their supported protocols. Configuring the gateway for a specific application is normally accomplished through a simple mapping process, which identifies the source/target addresses for each protocol as well as network-specific information such as baud rates, node addresses, and so on.
Gateway products that pass data from one communication protocol to another are available from dozens of vendors, and you can find a dual-protocol gateway to convert between almost any two protocols. Many PLCs today include both Ethernet and serial interfaces (and/or support added protocols via communication modules), and thus could potentially be used for protocol gateway functions. Most modern HMI products have multiple ports (for example, serial, Ethernet, and USB) and support more than one driver simultaneously, and therefore can be used as a gateway for the most popular industrial protocols.
Some gateway products are even more flexible. They include a host of hardware interfaces with user-selectable I/O drivers so a single product can serve a wide variety of communication needs. One example is SoftPLC Corporation’s Smart Gateway, which has an embedded 4-port managed Ethernet router and six serial ports, each of which can be configured for different protocols such as ASCII, Modbus, DF1, CAN/J1939, Modbus TCP, and many others (Figure 3). SoftPLC Gateways also provide hardware options to add support for a wide variety of fieldbus networks (for example DH+, Profibus, DeviceNet) and remote access (for example wireless, cell modem). In fact, SoftPLC Gateways can support up to 16 networks simultaneously with no data limits.
Appropriate use and selection of gateways provides connectivity to all devices, whether they are single sensors or controllers with thousands of data values. Gateways can make the IoT a practical reality.
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