According to Duane Grob of the system integration company Avanceon. Industrial systems. Fieldbus communications still remain a dominant form of industrial communications in place in most factories around the world that is the case for the systems that has been in place for a few years or more. But the vicarious nature of ethernet for the last decade or more made ethernet to be used more than other protocol.
Fieldbus is the network of choice for industrial manufacturers because they are dedicated in predictive in nature. You can predict when the messages will get to your field devices and the message package for compact and string lines for IO applications. While Ethernet may be fast but it is burden with network overhead, some unpredictable communications and are in high risk of losing data in the transaction. But manufacturers of industrial communication devices are quickly adopting the faster ethernet and supporting protocols by building industrial hubs, switches, routers and such that makes the communication more robust predictable.
The Fieldbuses that most people are familiar with such as Modbus, Ethernet/IP and Profinet that are basically fieldbuses with its protocol are converted into ethernet. There are larger development community that are working on the Ethernet evolution than was on any specific fieldbus. All other major manufacturers of field devices offer ethernet option with some multiple protocols over ethernet. There are already ethernet that are used on industrial landscape.
Fieldbus guarantee the delivery of its information as needed or when needed between machine or between systems which is a big knock of ethernet since its is not truly deterministic like fieldbus communication. Ethernet is expected to behave as predictable as fieldbus. Fieldbus is easy to diagnose a problem but the amount of information available on ethernet and the amount of information within the ethernet outweighs that these fieldbus are made over the decade.
Is Fieldbus still in place in some industries or manufacturer around the globe as it is costly to be replaced with Ethernet?
Replacing Fieldbus is not the generally primary reason on taking Ethernet insulation project. Looking for a way to replace devices, add devices and are looking for things that would give the customer better information which makes the reason to replace the fieldbus is much more on other things such as getting more diagnosis and be able to do that on a consistent single medium.
Getting more information from their field devices. Fieldbus system don’t offer to dig deeper into performance and the status of the field devices that would lead to a disadvantage to the owner. While Ethernet can be put on smart devices and add to instrumentation and its prefer connection is mostly the stand alone applications, which includes the ability to see problems arising and providing diagnostics before it takes the process down which makes the ethernet much better to use than fieldbus.
Other reason why manufacturer would prefer Fieldbus communication rather than replacing it with Ethernet
There are some manufacturers that are reluctant to open their operational system, the IT world. The information in the OT world is a prevalent as a device control since information is not just an add on it is as important as the device control. The only thing that would slow the ethernet connection will be the bandwidth, reliability and security but a lot of it is being handle in within the appliances and manufacturers.
Other reason as to why manufacturers would replace Fieldbus to Ethernet aside from the IT and OT. Installation of Fieldbus needs a proper installation requirements since its cables, connectors, etc. are a much more sensitive to its installation practices which causes time or debug when a fieldbus mediation issues such as improper installation practices or poor executed field repairs. While the Ethernet has a much wider understanding about it specially in the OT group, engineering group, and maintenance groups with a larger effort of Ethernet device manufacturers to design those type of issues. Replacing Fieldbus to Ethernet is considered to be a larger project and not just a primary reason for the upgrade but as a good practice then doing an upgrade task.
Is the Process industry or Discrete Industry the same when choosing either Fieldbus or Ethernet
There are different type of Fieldbus and Ethernet that are made specifically for some certain environment. There aren’t any different between Process Industry and Discrete Industry. Though Process Industry get a lot more information which makes this information invaluable if you really are using that information but if its just because its nice to have then better use ethernet connectivity.
The answers are all according to Duane Grob on the AutomationWorld Podcast
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