There is no longer a comparable show in the U.S., with many halls filled with automation suppliers and organizations. SPS, by the way, is German for PLC. SPS seems to be on the increase, while the Hanover Fair in April is rumored to be headed the other direction. PI, the international umbrella organization for PROFIBUS and PROFINET technologies, has a large booth in both fairs. Here is a very short video clip as I tried to walk the aisle on Wednesday of the show, which show management said attracted 48,595 visitors.
At the show PROFINET was ubiquitous, but I think the biggest news of the fair was PROFIenergy. First, PROFINET. Here is a ten-second pan of the PROFINET wall in the PI booth.
Now to PROFIenergy: PROFIenergy is an application profile for PROFINET that makes it easy for manufacturers to save energy. An application profile does not impact the underlying communication protocol (PROFINET), it specifies an arrangement of data and commands that is understood by the provider and the consumer of the information. Be sure to check out the article in this issue of PROFINET News for a detailed look at PROFIenergy.
Another highlight of the PI SPS booth was the IO-Link display. IO-Link is a fieldbus-neutral, point-to-point connection and communication method for intelligent IO. I think of it as HART for discrete because it superimposes a digital signal over the regular wiring. And it has reached critical mass. There were many suppliers who had adopted it; many tool providers; many semiconductor providers; many inquiries in the U.S.
IO-Link was visible in many other booths as well, including PTO member Phoenix Contact. Siemens introduced a new range of IO-Link products at the fair. Its IO-Link adapter has been available for a while. It allows a standard sensor to communicate using IO-Link, thus allowing some diagnostic information to be communicated (wire break being one example).
The PROFIsafe news the surprised me a bit was in the WAGO booth. They were showing their PROFIsafe IO for PROFIBUS and PROFINET. That’s not unusual and has been around a while. What was new was WAGO’s use of the iPar Server to save and restore configuration without requiring a configuration tool.
Although I spent most of my time at the SPS Show in the PI booth, I did get to visit the booths of some other PTO members. HMS was showing the PROFINET relatives in its Anybus family. IXXAT was showing its Industrial Ethernet Module that supports PROFINET. Hilscher was showing its netX chip family, which supports many networks including PROFIBUS and PROFINET. Turck was showing its PROFINET IO, PROFINET RFID, and PROFINET switch products:
PROFINET is not a star, but it can be when you want it to be, speaking of topologies, of course; in performance, PROFINET is a star!
I read a recent article in Control Design that featured this quote: “The biggest problem with Ethernet is the star topology. If I have ten devices, I need at least a 12-port switch, and that’s expensive,” explains ADCO’s Gilpin. “If each Ethernet-enabled device had a minimal switch built in, it would be simple to construct a ring topology network, and Ethernet adoption would progress at a more rapid rate.”
That “biggest problem” with Ethernet isn’t really a problem at all. PROFINET devices have had built-in Ethernet switches for years now. Some of the other Industrial Ethernet technologies used to pooh-pooh that idea, but are now following the lead of PROFINET. With PROFINET you can have any topology: star, line, tree, or ring… or wireless.
“But if I use a line topology and a device fails, the rest of the devices in the line are no longer available.” So observed a caller the other day as we discussed PROFINET topologies. True, I answered. And falling back on one of my favorite sayings, added, “There is no substitute for engineering.” If the rest of the devices in the line are impacted by the failure of the first device anyway, go ahead and use the line topology. If they are not impacted, perhaps a star, or more likely, a tree is appropriate. Do the engineering.
Even more appropriate might be ring topology, especially if communications is critical. PROFINET is the only Industrial Ethernet that provides several choices for ring redundancy, including one that is completely bumpless! PROFINET simply sends the message around the ring in both directions. When a PROFINET device receives the second message, the one from the other direction, it does not use it or forward it, it discards it. Bumpless redundancy.
For more of Carl Henning’s blog, visit www.profiblog.com.