Wireless PROFINET Questions – Asked and Answered

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I enjoy corresponding with editors about all things PROFINET and PROFIBUS.  But sometimes they don’t get to use my input.  So all my stuff wound up on the editing room floor for a recent article on wireless.  To save my good stuff from extinction, here are wireless questions, asked and answered.

Before you begin, remember my pet peeve about “wireless”- it’s is not just one thing!  You’ll find the whole rant at “Wireless or Wireless.”

1. What’s the current state of wireless networking today, and what’s making wireless easier to implement?
As with many technologies adopted by industry, commercial wireless is proliferating.  Many, many folks have wireless at home and in their office.  When I ask students at our one-day training classes if they are using wireless, few are.  But there are more and more projects being done.  I cite six of them in a recent blog post: “Wireless – It’s More Prevalent than You Thought.”  And that list does not count the Camotion story from the 2006 safety movie; you can view that excerpt here:

2. Are wireless protocols becoming more coordinated and allowing more interoperability?
In the Industrial Ethernet world, the popular three (PROFINET, EtherNet/IP, and Modbus TCP) can exist on the same infrastructure just fine.  (They can only interoperate through gateways though.)  You can have all three on the same Ethernet cable or wireless connection.  Of course, just because you can doesn’t mean you should.  The only caveat is that EtherNet/IP does multicasting which must be constrained using IGMP (Internet Group Management Protocol).  As long as Ethernet switches (or Wireless Access Points) that support IGMP are used, coexistence is possible.  The motion Industrial Ethernets like EtherCAT have to be on their own isolated network and they can’t go over a wireless link.  Of course, with PROFINET’s motion network extension (PROFINET IRT), we can’t go over wireless either – the time delays are not tolerable.

3. Are application-specific audits of wireless coverage areas still needed?
Yes, in all but the simplest situations.

4. What do users to need to learn to begin implementing wireless tools in their process applications?
They’ve probably got some basic knowledge from home, but education is definitely the key.  PI North America offers a webinar as a starting point.  But the suppliers are better positioned to help on specific projects.

5. What should be on my to-do list to get this technology up and running at my facility?
Education and supplier engagement.  Start small if you can.

6. How can wireless be made secure?
On the Industrial Ethernet side, WiFi has robust security built in.

7. Do you know of any specific examples, case studies, system integrators or end users who have adopted a wireless solution recently, and could talk to me about their experiences?
Lots, see my answer to question 1.

8. What advice do these users or you have for readers about implementing wireless?
Wireless is no longer bleeding edge; use it where it makes sense.  It makes sense to avoid using slip rings for rotating parts or bars for linear motion.  It makes sense where the atmosphere is hostile to cable and connectors.  It makes sense for AGVs.

–Carl Henning

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