Industrial Ethernet Basics - Part II
In industrial communication, Industrial Ethernet represents a milestone for the automation of production and manufacturing processes and building automation. However, what is Industrial Ethernet and what do more and more companies worldwide expect from this technology?
What exactly is Industrial Ethernet?
Until today, most people do not really know what Ethernet means. This term frequently occurs in connection with so-called “smart homes”. Ethernet is the network that all actuators in the smart home use to communicate with each other. If you consider the smart home - the “thinking house” - as the body, the Ethernet would correspond to the nerves and blood vessels through which the information is transferred from the brain to the individual body parts - the actuators. In the following, it will be explained why this metaphor is not 100 % correct.
Industrial Ethernet represents an adaptation of Ethernet technology to production processes. It accelerates the communication and synchronization of the actuators participating in the process.
This leads on to the question:
How does Industrial Ethernet function?
Ethernet is based on the master-slave principle: The actors of the module controlling the processes are the slaves. These are connected via a collective line to a master, which also represents a kind of central control of a group of slaves. And here comes the point why the “brain metaphor” (see above) is not 100 % correct: If it increases the efficiency of the system, the individual slaves can also communicate with each other. That would be as if the little finger of the right hand could send a message to the little toe without taking the detour via the brain. This serves to reduce the load of the central control, which can then reduce the energy consumption
What can Industrial Ethernet do
Production and manufacturing processes become increasingly complex and multi-layered. The demands for the control of these process increase correspondingly. Fieldbus systems that were in the high-tech sector only 20 years ago have not been able to compete there for some time. Here, one of the characteristics of Ethernet and especially Industrial Ethernet comes into play: The so-called real-time Ethernet, also called Fast Ethernet, transfers data with 100 Mbps. A vertical system structure further enables communication between several system components without the risk of data collision. The cycle times of the synchronization of the system are in the microsecond range.
Furthermore, the individual modules of the Industrial Ethernet network can be reprogrammed relatively quickly, which enables a new combination of the network components according to the building block concept. Such a high flexibility can scarcely be found in an industrial communications system.
What are the advantages of Industrial Ethernet?
Because of the ever accelerating globalization, more and more companies are engaged in optimization and efficiency increase of their operation. This means that they want to improve the ratio of production costs and production efforts.
Commercial users can expect the following benefits:
- Savings through less waste because of more precise control of production processes. Dosaging processes in particular can become considerably more efficient.
- The high flexibility of Ethernet systems creates the ability to plan for the short-term and medium-term compared to the conventional planning times. The resulting improvement of the capacity to manufacture to order reduces stock.
- In connection with this, the downtimes of the operation installations can also be reduced.
However, the customer also has an advantage from Industrial Ethernet:
- The ability to continuously monitor measuring values and tolerances can improve the quality of products overall.
The installation of different Ethernet systems is done uniformly. The field components of all Ethernet vendors are compatible with each other. The user can check this by means of a certificate intended for this purpose. Once installed, an Ethernet system also offers redundant routes of transmission in case of failure of a data line, so that the operation is impaired not at all or only slightly. Further advantages with installation and maintenance of Industrial Ethernet are:
- Considerable reduction of the installation efforts, as only a single cable is laid.
- With the corresponding programming, the information collected in the entire system can be accessed from any location.
- Troubleshooting is facilitated considerably in comparison with other, older systems and the time is shortened.
- The training of installation as well as maintenance personnel requires less time and fewer efforts.
- Uniform confederation tools, for example the so-called sniffers, exist for maintenance, checking, and repair of all Ethernet systems.
In order to keep the long-term costs for the users as low as possible, the large Ethernet vendors some years ago started an initiative for the creation of uniform maintenance tools. An international certificate guarantees the compatibility of the various field components.
The three most widely used concrete methods for maintenance are:
- Field Device Control (FDC)
- Tool Calling interface (TCI)
- Electronic Device Description Language (EDDL)