Hanover Fair – Day 2

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The show does not seem to have a major theme, focus, or breakthrough according to the fairgoers I’ve spoken with.  But I think today’s word is “coopetition.”  This results when competitors cooperate.  I think the ECT is a prime example.  The ECT is the EDDL Cooperation Team made up of Fieldbus Foundation, HART Communication Foundation, Profibus International, and OPC Foundation.  The first three organizations represent competing technologies in industrial automation, but they’ve come together to cooperate in providing users with a common solution.  That was extended today with the addition of the FDT Group to the team.  From the press conference Q&A:

Why did the ECT and FDT Group decide to work together even though each claims to have the better solution for device integration?

Currently, there exist two technologies which are offered to end users. On the one hand they overlap to some extend, on the other hand they have a different scope of application. Unfortunately, existing market dynamics forces users in some cases to choose one of these two and offers no migration path from one to the other. Because this approach is unacceptable for end users, there is a need for a single unified solution.  Additionally, manufacturers are currently investing in parallel development efforts to support two technologies. For these reasons, we decided to join efforts and develop a common Future Device Integration (FDI) architecture.

An often overlooked goal of the new cooperation is to include factory automation within their scope.  Other important points:

  • Platform independent
  • Compatible with existing EDDL and DTM based device descriptions
  • Specification due next year
  • Concepts were demonstrated in the PI booth
  • Will become an international (IEC) standard
  • Initially applicable to HART, PROFIBUS, FF, and PROFINET, but will be available for adoption by other fieldbuses.

This is just the beginning of course.  The agreement is in place.  The photo op is over.  The press release is released.  The PowerPoints have been shown.  Yet to come is the completion of the spec and, finally, adoption and implementation by the vendors.

Coopetition number 2.  According to a press release here, Schneider Electric increased their participation in ODVA, the consortium for DeviceNet and Ethernet/IP (competing technologies to our PROFIBUS and PROFINET).  To some extent all the consortia (PI, ODVA, FF, OPC) exemplify coopetition – competitors uniting for a common purpose.  Schneider is also a member of PI.  In fact, many of our members belong to more than one consortium.  As far as the significance of this increased participation, I don’t know.  What I do know is that one word that I saw on Gary Mintchell’s blog from his interviews with the principals should be alarming: “encapsulation”:  “There will be a special interest group (SIG) established by ODVA to work on the protocol coordination to encapsulate Modbus packets within CIP so that they may be passed on the CIP network.”

To me encapsulation is a less than ideal.  It introduces one more step in the process which adds to the response time.  And encapsulating it in TCP/IP or UDP/IP adds to the uncertainty of the delivery time.  The University of Michigan presented some startling graphs at the Industrial Ethernet Symposium last October comparing the real-time performance of Ethernet/IP (which encapsulates CIP within UDP/IP) and PROFINET (which goes straight to Ethernet, bypassing the UPP/IP layers).  The PROFINET graph shows the response times clustered tightly around 8 milliseconds.  The Ethernet/IP graph shows much greater deviation around 8 milliseconds PLUS many response times clustered at 16 milliseconds.  U of M has subsequently published those results:

PLC Communication using PROFINET: Experimental Results and Analysis

Experimental Determination of Real Time Peer to Peer Communication

Characteristics of EtherNet/IP

The press release says products will be available in 2008.  But there is no reason to wait; PROFINET can communicate to Modbus today through a proxy… without encapsulation.

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