Ethernet Goes Industrial, But Which One?

Very good post, "less expensive and easier ways to connect and monitor machinery" The next leap will come from those that can add control to the list.

No doubt that networks are already used to control machines, but they tend to be independent from ethernet, to allow for a deterministic protocol. There is a certain amount of predictability built in. Be very interesting to see what happens in the near future.

thanks for the link

could someone enlighten me as to why consumer grade Ethernet is not/cannot be used industrially? is it because of noise interference? maximum cable length before signal degradation? Thanks!

Yes both interference and cable lengths are obstacles, however both are overcome by proper installation and hardware.

Ethernet communication is like 'burst firing', and update times are based on network traffic loading. This is not a problem if the intent is to simply track production, monitor machine performance and parameters for Quality Control, or other passive reason that improves efficiency.

Most factories have a layered network plan, where the lowest level network (not ethernet) controls the machine, by monitoring parameters and adjusting setpoints. In order for a computer (PLC) to monitor and control a machine process, the update times should be fixed and predictable. Otherwise it is hard to calculate 'how much to adjust the knob' if you are unsure of how long it will be before you can 'see' the meter again.

Upper layers of the network plan are for business communication systems like emailing, order taking, and other higher functions. These can use the less reilable, but more open ended ethernet protocols. If this network fails or slows down the production is not impacted.

What is happening now is the business systems want to get 'closer' to the machine control; perhaps for better quality control, or tracking of raw materials, faster delivery cycles or whatever. This can be accomplished a couple of ways, usually the PLC can talk to both networks and becomes a 'bridge'.

So to answer your question ethernet is used industrially, all over the plant floor, it just is not the best fit for the lowest level of control. This may be a good thing, since networking machines and business computers on the same cable opens too many possiblilities for hacking, or hijackers. Plus it may also be 1 step closer to humans losing control and the machines taking over.

Ethernet IP or Allen Bradley's version of determionistic Ethernet is gaining some ground for device level network control for i/o.

I am a Sales Engineer, just go to Turck.USA.com and find information on BL67 Ethernet IP/TCP/IP i/o media. I work in the Atlanta area and Shaw Industries and Coca Cola Enterprises are just a couple of pioneers in this area so far. The key seems to be the use of Managed switches instead of inmanaged switches. We also commonly use ethenet for control using machine vision products.

Thanks

John Jones

What Mevel123 is saying is right. In other words, standard Ethernet is not time-critical where as the plant level communications need to be real-time. Any delay in the communications between machines OR operators and machines will affect the performance of the machine(s). There is a solution to this in the form of Real-time Ethernet but, I think it is still in its infancy.

As a novice.. what does this mean as far as the current internet is concerned?

Marge

It means nothing to the current internet. As a novice or as an expert:)