Editor’s Note: This article was created with expertise from Andreas Dreher, the strategic technology manager at Hirschmann Automation and Control.
Earlier this year I published our first article on the Smart Factory of the Future. It described a vision of manufacturing where systems are more intelligent, flexible and dynamic. In the future, machinery and equipment will have the ability to improve processes through self-optimization and autonomous decision-making. This is in contrast to running fixed program operations, as is the case today.
The structure of industrial automation systems will also change. There will still be a separate dedicated field level with actuators and sensors, but in the long term many functions located above that will likely move to high-performance servers located in a server cluster or in a “cloud”.
“Cyber-physical” systems will be important, with feedback loops where physical processes affect operational programs and vice versa. An example of a cyber -physical system is the Smart Grid which aims to improve the reliability and efficiency of the electrical grid system through collecting thousands of data points and acting on them using software management tools.
Let’s now consider the manufacturing LAN and its communication systems. How does it need to change to realize the vision of the Smart Factory?
The Smart Factory of the Future will consist of systems that are more
intelligent, flexible and dynamic than the ones in use today.
Photo courtesy of BMWblog.com.
High Numbers of Connected Devices using Industrial Ethernet Protocols
The number of connected devices in a future Smart Factory LAN will clearly be higher than it is today. This is because there’s a need to collect as much real-time data as possible that is relevant to the process. It’s estimated that the quantity of connected devices will double or triple.
The challenge will be connecting this large number of devices at the field level in a simple, cost-efficient manner. Of course demanding requirements for performance and reliability will still need to be met.
The use of field busses will decrease significantly to make way for consistent and unified communication via an Ethernet network. All communication will be based on IP protocol families and Ethernet will be the underlying communication protocol, regardless of whether the connection is wired or wireless.
Increase in Use of Star Network Topology
As is the best practice today, future networks with high numbers of devices should be hierarchical to simplify network management and operation. The field level should be segmented into manageable communication cells, such as by production units, or any other logical or physical units. The difference will be that the amount of data generated in the cells will be significantly higher than it is today.
The network will still use star, line or ring topologies, or a mix. The use of star topologies will increase, however, because they have some advantages – such as lower latency and higher reliability – compared to other topologies.
The disadvantage of a star topology is that the failure of a switch will disconnect all attached devices. Nonetheless, simulations clearly show that one larger switch has a higher total reliability – more precisely, a higher Mean-Time-Between Failure (MTBF) – compared to a system consisting of many cascaded, small switches. This is the reason why star topologies are used in data centers today.
Lines or rings will be used too, because certain topologies might have advantages in cabling. Additionally, the use of more complex structures, such as extensively meshed network topologies, will increase. With the adoption of new protocols, these networks will need less management efforts.
The Smart Factory of the future will use network topologies familiar to us today, but with higher numbers of connected devices delivering higher amounts of data.
Wired or Wireless?
In the future, will all devices be connected by cables and wires or will everything be wireless? In the industrial applications of the past, communications were almost exclusively based on wired networks.
In recent years, however, wireless systems have found increasing use. They have been adopted most often for non-critical industrial applications, such as configuration and monitoring, transfer of peripheral data and for mobile worker applications.
The challenge with radio is that it is a “shared media,” i.e., all devices share a certain frequency range. If a device is transmitting, the channel is busy. Radio communication can also be error prone. Other radio systems, other electromagnetic influences or objects can affect transmission and significantly deteriorate quality, bandwidth and latency.
The sporadic loss of data packets is the norm in some radio systems and has to be handled by the applications. This is done at the expense of throughput and latency. While this may be acceptable in enterprise wireless deployment environments (like in offices and businesses), industrial wireless products need to be designed from the ground up for reliable performance.
Well-designed industrial wireless products are now employing techniques like:
- Enhanced electrostatic discharge (ESD) protection for hazardous environments
- Wireless mesh technology for quick network reconfiguration and service assurance,
- Redundancy protocols like Parallel Redundancy Protocol (PRP) for wireless communications.
These intelligent technologies help industrial wireless applications adapt to radio channel performance issues and deliver much more dependable systems.
Nonetheless, reliability requirements will drive the choice of communication technology, wired or wireless, in the Smart Factory. Significant use of wired communications can be expected, but the flexibility of deployment of wireless connectivity will drive increasing usage of suitable industrial wireless products.
Communications in the Factory LAN
My next article in this series will continue to look at the requirements for communications within a manufacturing site’s LAN for achieving the vision of the factory of the future. I will look at data rates, cyber security, reliability and other aspects of what’s in store for upcoming industrial communications systems.
What do you think about the Smart Factory? Are you taking steps to enable it? I look forward to hearing from you.