I’m in Las Vegas this week. It’s hot and very sunny. Pretty bad for my bald shaved head. Pretty typical Vegas summer weather.
I went to the Bellagio, probably the most recognized display in all of Vegas. Everyone who comes to Vegas has to see the fountains. One of the coolest projects I ever worked on was a comm interface for the drives that power the pumps for those fountains. I had a real behind-the-scenes look at how they are retrieved from the lake and what the insides of them look like. Not what you might imagine. Pretty simple and mundane technology powered by Rockwell PowerFlex Drives. Good choice of drives for that application.
While I was here a question was put to me about the USB ports on the newest versions of the ControlLogix L1, L2 and L3 PLCs. These things have been rolling out since January and they don’t have the old, comfortable serial ports anymore. This guy wanted to know what I thought about the move.
I honestly have to applaud Rockwell for this. It’s a good move. From their perspective it lowers costs, saves space and provides higher speed operation. That’s all really good news.
From the users perspective maybe not so much. But you have to understand that when you are a massive organization with hundreds of thousands of users, you can’t stand still. And any move you make is going to impact somebody negatively. That just can’t be helped. And it’s true in this case.
The old serial ports were dual use. Since the days of the PLC 5 they were used to download programs and communicate with the editor. They did a pretty good job of that even with the now glacially slow speeds provided by serial comms. The good news is that this is now being taken over by USB and we’ll be able to load programs and access the data table and everything else at much faster rates. Big Hurrah for that!
But there is some functionality that was lost. The old serial ports had some limited capability to move data in and out of the PLC. The functionality varied with various models of PLC but there were instructions that could send/receive data over those ports. And there was DF/1 communications. You could read/write data table values using the serial port and the DF/1 protocol. It wasn’t fast or elegant but it worked.
Well, that’s apparently gone (at least for a while). There is no capability in the new processors to send/receive data to USB devices.
I understand why. The way USB works is that when a device is identified, its device ID tells the host to load a particular driver for that kind of device. I am sure that RA didn’t want to fool around supporting lots and lots of USB device drivers. The words “support nightmare” come to mind.
So, now all those guys that were communicating data over a serial port are out of luck if they want to use one of the newest versions of PLC. But that had to happen. Progress happens. Rockwell did the right thing here.
But, luckily, I found a solution for these people. And it’s right here in our product line. If you have an Serial ASCII device and need to send ASCII data to a PLC the 435NBX is the perfect device for you. It’s extremely easy to setup, integrate and operate. We get tons of great feedback on it.
And if you’re a guy with a USB device and need to connect that to a PLC, I’ll soon be able to help you with that. That’s not announced but it’s coming soon.