By Jim Montague, executive editor
I can still hear the cries and echoes. Some are closer than others.
Fieldbuses are too complicated. Digital network components are too expensive. Ethernet isn’t deterministic. Over-molded RJ-45 connectors aren’t rugged enough. Point-to-point wiring is the only way to be sure you have a reliable signal. The programming and configuration are too complex. I can’t maintain an industrial network. We’ve always used 4-20 mA wiring. If it’s not broke, don’t fix it. I just don’t wanna! Waahhh!
OK, stop whining and blubbering for a minute. There’s little or no cause for panic.
Truth is, implementing a digital, industrial network is simpler and easier than it was even a couple of years ago. Even rookie users can determine quickly which network is right for them online, get a little hands-on training at one of many local seminars, use a test kit to check how a network will serve in the application, easily install and configure it with minimal fuss and start gathering some useful data. It’s even simpler to tie plant-floor networks to upper-level management systems.
Sure, there’s always the risk that this is more sunshine being pumped up my XXL khakis and that I’m just spreading happy horse hockey. That’s always a fair criticism.
However, many of the folks who first educated me about industrial networking try to reassure me, and indirectly you, that it’s truly becoming easier to test drive and implement a digital network because many of the tasks associated with it are either automatic or involve a few points and clicks for a whole system, rather than writing or inputting lines of code for dozens of individual devices or I/O modules.
Helge Hornis, Ph.D, manager of Pepperl+Fuchs’ Intelligent Systems Group, says each of the 62 available addresses on an Actuator-Sensor Interface (AS-i) network can be assigned using a handheld programming tool. See this issue’s cover story, “To the Terminal, and Step on It,” on p14 for more on device-level networks. After connecting the node to AS-i’s flat, two-wire cable, users just dial in the address they want to give it.
Likewise, he adds that gateway modules between device-level networks and higher-up fieldbuses now can take data they see, pick up available device addresses and enable users to confirm what’s on their network. Adding traditional devices to networks often used to require users to set dipswitches, type in software-based changes and then download identifications to PC-based cards in the modules or elsewhere on the network.
“Once users learn how fast device-level networks are to set up and run, very few ever want to go back to the old ways of hardwiring or doing a lot of PC programming,” says Hornis. “For instance, I do a live demo when I visit users now. We run an AS-i cable through the room, give each person an I/O node, and they usually have them connected and up and running in about 15 minutes. What makes this even easier now is that if you have 20 I/O nodes on a network and you want to add five more, you just install them, give addresses to the handheld and hit one button to update the gateway, so the I/O device automatically will show up as an I/O image on the PLC. In the past, users had to add I/O cards and might run out of rack space, or add wiring from the field to the PLC and then program the device to the PLC.”
These improvements in setting up and operating digital networks aren’t confined to AS-i and device-level solutions. Most fieldbuses, Ethernet-based systems and industrial networks of all types quickly seem to be adding capabilities to make themselves easier to use. This is undoubtedly because each hopes to emerge as the dominant solution both in its originating industries and beyond. Whatever. I’m just glad that I don’t have to look for a driver every time I plug my USB-enabled mouse into my laptop.
For the latest news, capabilities and training, I usually find it best to start with the web sites of the main digital networking organizations, including as-interface.net, fieldbus.org, hartcomm.org, ibsclub.com, modbus-ida.org, odva.org, us.profibus.com and a few others.
So, if you’ve delayed exploring, learning about and perhaps implementing a digital network, now is the time to move beyond point-to-point hardwiring, save some copper and collect some of the values your colleagues can use to run your business better. Don’t wait. Even if it’s not broke, you still can make it better.
