I would like to discuss the benefits of using Ethernet as backbone for automation control systems. It’s a technology that enables controllers to connect to this powerful medium.
There are plenty of values in using Ethernet as an industrial communication protocol, but for the purposes of this blog I will focus on three key benefits…
The 3 values I would like to discuss are Ethernet:
For me, Ethernet openness is the ability to mix different application protocols on the same media. These different application protocols provide different services to best fit with a business’s operational needs.
For industrial communication, the ODVA (Open DeviceNet Vendors Association) specifies Modbus and Ethernet industrial protocols to enable communication between controllers or between controllers and operational visualization where determinism is a must.
On the other hand, during operations there are other needs such as diagnostics, time synchronization or IT connection. Using Ethernet will allow businesses to use existing standards such as web based diagnostics over HTTP, time synchronization with NTP and IT connections over web services.
From a business standpoint this openness means a cost effective solution and freedom of manufacturer selection.
Ethernet transparency is also a key point and a great technology benefit. The drawback of this transparency is the administrative requirement to ensure security of your network to avoid intrusions. This being said, being able to securely access, your data from everywhere on your intranet has lots of advantages. I will point out two:
Process automation has a huge impact on the energy consumption costs for a company. Having Ethernet on process units at a lower plant level will help to access data straight away, without the need of middleware. Data consolidation will also enable businesses to manage and forecast their energy consumption, and at the same time decrease it without infrastructure evolution.
I pointed out the need to connect the control system to the IT world; Ethernet is the IT protocol so the control system is, de facto, integrated with your IT intranet. The transparency of Ethernet will help businesses to have agile operations by directly connecting manufacturing execution systems with no additional development costs.
There are plenty other advantages to access data from control systems at higher levels of the enterprise such as asset management, production data, remote maintenance, evolution and much more. As I pointed out, there is an administration cost to manage the security of your installation and to maintain it. But Ethernet will avoid the need to develop specialized middleware for energy management or MES connections, for example. The maintenance will only occur at the network level and does not need to be dedicated to specific areas by specialized teams.
Nowadays Ethernet allows different topology over different media. This flexibility helps to complement plant topology at the right cost.
The bus topology will provide low cost connection, with a daisy chain feature, where availability is not mandatory. The use of fiber optic cable will enable a long distance network whilst retaining a high bandwidth.
When designing the topology, it can help to have distributed device from a single part of the plant. Star topology can be used to secure network devices with critical data, thereby avoiding “man in the middle” attack (where a cyber attack is aimed at the communication between the endpoints on a network).
The ring topology is a typical architecture in automation, as most of the time network availability is a requirement and designed to allow at least with one fault tolerance.
The ability to mix those topologies within a plant helps operations managers to adapt network layouts within physical and availability requirements.
To conclude, an Ethernet backbone increases the agility of an enterprise’s operations. It enables evolution without any change on the infrastructure itself. This being said we understand that having a controller that is fully Ethernet enabled will reinforce all of those advantages.