1. Control shifts from centralised to decentralised. PLCs (and DCSs) used to be large, monolithic, scarce, and expensive equipment. The wiring for all automation projects were sent to them. Fieldbuses allowed control to shift away from the centralised PLC and closer to the equipment being controlled as distant I/O connections moved from ‘dumb’ to ‘intelligent.’ As the number of intelligent I/O connections grows, more bandwidth is required to communicate between them. As the number of devices grows, so does the need for greater address space; enter industrial Ethernet, which offers improved bandwidth and a larger address space.
2. Networks: from numerous to a single. Learning various tools, establishing multiple infrastructures, and requiring multiple interfaces between them are all complications that come with having more than one bus. Initial engineering and ongoing maintenance are substantially simplified with a single bus managing I/O needs, peer-to-peer integration, motion control, safety, and vertical integration to plant-wide systems. Although one is ideal, actuator and sensor buses such as AS-i will almost certainly continue to exist. Industrial Ethernet requires far too much wiring and is prohibitively expensive in a 1-bit context. However, industrial Ethernet excels in other areas:
When most people think about industrial Ethernet, they think of input/output links. Their idea is to convert a fieldbus to an Ethernet network. While replacing a fieldbus is one of the most significant components of an industrial Ethernet network, it will not be the only network that can be utilised for (nearly) all plant automation. All branches must be connected to an Ethernet switch (for full moxa switches in Malaysia, see here). A fieldbus benefit—the bus—is lost as a result of the ensuing star topology. Recognizing this, several manufacturers have begun including switches into their products, allowing for the creation of a ‘virtual’ bus structure.
PLC-to-PLC or equipment-to-equipment integration are examples of peer-to-peer integration. Integrating the equipment into a unified production line is a difficult task that necessitates programming of each individual control device on each piece of machinery. Profinet allows each piece of equipment to be ‘componentized’ by utilising a proxy to connect Profinet to the equipment supplier’s standard control network, whether it’s Profinet, Interbus, DeviceNet, Modbus, serial, or whatever. This method also makes it simple to connect current equipment—no there’s a need to scrap the entire network and start again.
Motion control may appear to be less of a concern in the discrete automation industry, but according to an ARC Advisory Group report, motion control accounts for 38 percent of the ‘discrete’ market. So, if there is to be a single network, it must be capable of handling motion control. Profinet, for example, can manage 150 axes in 1 millisecond.
Safety. Safety circuitry can now be implemented in PLCs and over fieldbuses, according to North American code. Safety protocols have been announced or released by a number of industrial Ethernets. Profinet is a 5-year-old Profisafe extension that includes Profinet as well as Profibus.
Vertical integration is a term used to describe the process of When the physical layer (Ethernet) and protocol layers (TCP/IP) are the same, connecting to plant-wide systems is easy.
3. Connectivity options: wired and wireless. Wireless connections are required for some projects, while others are used for convenience. When troubleshooting or commissioning a line, wireless might make it easier to be where the problem is. Control signals from moving equipment, particularly rotating equipment, are frequently required. Using festooned cables or slip rings can cause maintenance issues and signal loss on occasion. Wireless Ethernet connectivity, such as IEEE 802.11, is a well-understood and well-supported method of obtaining control signals from moving equipment.
4. Information technology: from a state of ignorance to a position of strength. Control engineers used to disregard office networks. Industrial Ethernet may now use the same tools that the information technology (IT) department employs for the office network, as well as the knowledge and experience gained from overcoming the IT/control engineering divide. That departmental divide must be broken down.
5. Plant Networks, which range from closed to open. Users were confined to one vendor and a small number of devices during the proprietary bus era. There are more vendors to select from and more goods accessible with open networks.