Higher level automation components such as PLC’s, Drives, and HMI’s communicate with each other through industrial networks. These allow them to pass more advanced data back and forth between them as opposed to a single true or false signal from a single wire. There are many different types of communications, types of hardware, and topologies that allow these networks to operate. The most common types of industrial networks are Ethernet IP, Profibus, and Profinet, but there are many others as well. Modbus, Ethercat, Canbus, and Controlnet are a few of the many other types that we see in applications.
Ethernet IP is probably the most common protocol and operates under the common industrial protocol. You see these types of networks everywhere, in your house and in businesses connecting computers to the internet. These usually have an RJ45 plug to terminate an 8-wire cable, but also have other termination styles like an M12 connector. There are also different styles of ethernet cables that transmit different amounts of data, and at different speeds. The topology, or the way the network is organized, of an ethernet network is either bus shaped where everything is connected in a single line, or star shaped where each device connects back to a centralized point like an ethernet switch.
Profibus is a fieldbus type of network that was created in Germany and popularized by Siemens. This type of communication uses a shielded twisted pair of wires to transmit information. They are terminated with a profibus connector that has a terminating resistor. These connectors either allow the network to continue to another device or stop at that connector by turning the terminating resistor on. Profibus uses a bus topology, so it looks like a single line. Profibus repeaters are employed periodically to expand the network when necessary.
Profinet is like a mix between Ethernet and profibus. It has faster transmission speeds than ethernet and was designed for communication with industrial controllers like profibus. It uses a special shielded cable that has 4 conductors instead of 8, like ethernet. These are sometimes terminated with an RJ45 connector similar in shape to the ethernet cables, and other times with an M12 connector. Like the other networks, they can be organized in either a bus or star topology. Many regular ethernet switches are also capable of handling profinet communications, but it is always important to double check if a switch is capable!
Beyond just the hardware differences there are also other differences such as how data is processed, and what types of software is required to connect to those networks. It’s important to have all the tools necessary to connect to whatever network you might encounter, or even how to handle multiple networks that connect to each other using a gateway. Here at Premier Automation we have experts in designing, implementing, and troubleshooting just about any type of industrial network.
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