PROFINET Q & A from Louisville

Our course evaluation form asks some specific questions with check box choice answers, but I think the most interesting are the open-ended questions.  Two of those are topics you would like to see covered in greater detail and topics in less detail.  In Louisville there were a few responses for topics attendees thought we should cover in less detail:

            Theory (was good, but was a lot of information in a short time).

            Sections covered in webinar prerequisites.

This remains a tough balance to maintain.  We know that not everyone is familiar with Industrial Ethernet, but have not had time to view the archived webinars.  Our compromise it to try to cover the essentials of Industrial Ethernet very briefly.  You can view those webinars here whether you are coming to a class or not.

Here’s the list of items attendees asked to be covered in greater detail:

            Integration from PROFIBUS to PROFINET

            Application examples.

            Application examples – show us the code!

            CBA configuration.


            PROFINET topologies.

Spend more time on security.

Differences between various Ethernet bus systems.

Integration from PROFIBUS to PROFINET.  Our coverage of this is fairly brief, but this integration is also very easy.  Basically, you add a proxy between the networks.  A proxy is like a gateway in that it interconnects two diverse networks, but unlike a gateway it is part of the PROFINET specification.  A gateway is typically the product of a single vendor who happens to know both networks.  With a proxy the mapping between the two networks is fixed in the specification.  For example, when we specified the HART proxy we invited the HART Communication Foundation to participate in the Working Group.

Application examples.  We do try to show some of the code, but time really limits us.  For more detail (and more code) I recommend the week-long PROFINET Certified Network Engineer class.  We don’t have any available for the remainder of this year, but watch the website for next year’s schedule.

CBA.  Component Based Automation is the name for our peer-to-peer networking technique.  It allows horizontal integration without programming.  A simple GUI allows graphical configuration instead.  For more detail I recommend reading our “PROFINET Technology and Application” system description beginning on page 9.

PROFINET topologies. PROFINET allows star, tree, (virtual) line, and ring topologies.  I qualify line as “virtual” because it is not a bus topology like PROFIBUS, just a virtual bus.  With PROFIBUS the wiring passes unbroken through connectors that attach to the devices; with PROFINET, the wiring goes into and out of an Ethernet switch.  It just happens that the switch is built into the device.  This gives us the best of both worlds – Ethernet and a linear topology.  A topology discussion would not be complete without…

Security.  In addition to the topology considerations within the automation environment, the interconnection to the office and beyond must be considered.  While we cover this in the class, the details are in our long-published “Security Guideline.”  It’s available online.

Differences between various Ethernet bus systems.  We do offer a competitive comparison chart for each area – IO, CBA, motion control, etc.  Our past experience has been that if we dwell on this too much we are accused of being overly critical of the competition.  So we present this as succinctly and factually as we can.  We also hand out the booklet, “PROFINET or the story of Pretty Polly, Sweet Sue, and the White Knight” which goes into additional detail.  You can order your own downloadable or hard copy edition on the booklet from our website.