Networking / I/O

So long, Remote I/O, and thanks for all the connections

Retirement of Remote I/O prompts a look at what’s on the network

By Rick Rice, contributing editor

As I celebrate 30 years in control design, I realize my infection by the bug, so to speak, goes back even further to 1980 when the seemingly perfect meld of the start of my military career in communications and the advent of the home computer combined to create my destiny. A lot of time has passed since those inauspicious beginnings, and the thought of this has put me in a reflective mood, so I thought it would be good to talk about what I have seen over the past 30 or so years and where the future is leading us.

Growing up in semi-rural Ontario, Canada, in the ’70s, we had little exposure to technology. Our days were filled with school and chores. We had a rather large garden in our back yard, and my youth was spent learning to plant and raise crops. In the late 1970s, the citizen band radio was all the fad. Who doesn’t remember the “Smokey and the Bandit” movies? Every kid wanted to have a CB radio and reach out to the world. I was one of those kids.

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Machinery tends to last longer mechanically than electrically.

I credit my early fascination with technology to my father. He recognized my keen interest and nourished that thirst for knowledge by giving me electronic kits from Radio Shack for birthday and Christmas presents. I fondly remember those kits as the foundation of my electronics journey. Each kit had about 15-20 projects in it that used the various components anchored to the board. They had spring terminals that one would flex with a plastic tool while inserting specifically colored wires between the coils to make a connection. The color of the wire corresponded to the length of the wire. Beginner projects ranged from a simple switch and light to buzzers and sound generators. More advanced projects even had tuners and dials to make a radio that I could use to tune into the local radio stations.

The early ’80s brought me to the end of my high school years and my enrollment into the military. I served 12 years in total, most of that attached to a signals unit near my hometown. My trades training brought me radio/teletype, cryptography and telephone lineman skills, but it was advent of the home computer that cemented my fate and delivered the final push into what was to become my career. It was, once again, my dad who provided me with the necessary elements to launch the next step in my journey when he bought a TRS-80 Model I computer from Radio Shack. Dad claimed not to know much about such things but thought that I could help him to learn how to use it. Home computers in those early days are nothing like the desktop and laptop devices that we use today. Ours had a whopping 40K of RAM, and a later upgrade gave us 80K. I remember how exciting it was to have that 80K of computing power. There wasn’t much in the way of user programs on those early computers, so anyone wanting to do much was compelled to learn a programming language called GW-Basic. I didn’t learn until much later that GW was, in fact, Gates William or, as we know him today, William (Bill) Gates, co-founder along with Paul Allen of a company called Microsoft. That’s right. Bill and I go way back.

The TRS-80 Model I gave way to a TRS-80 Model III. We traded away the cassette tape storage device for this new thing called a floppy disc drive. This amazing device allowed us to create programs and store them on a device that could be opened up later to retrieve the program and execute it. The process was slow as the computer would exchange memory segments with the 80K base memory through a process called caching. Next came an internal drive by some company called Winchester with ever-increasing storage limits with each new upgrade. Floppy drives got smaller—from 8 inches to 5.25 and then to 3.5 inches—and internal hard drives got bigger. Terms such as 16-bit, 32-bit and 64-bit came into use as processors became more and more powerful. Bigger processing means more memory use, and memory chips got bigger and bigger storage capacities to match.

Wow, that was a fun trip down Memory Lane. It’s hard to look at the laptop, tablet and smart phones of today as anything resembling those early desktop computers. I am obviously an IBM geek, but an equally parallel explosion happened on the Macintosh products from Apple. You can’t look very far today without seeing an iPhone or iPad or iPod.

Riding along this interstate of technology has been the controls industry. Steve Jones wrote a great article, “A Walk Down Automation Programming Memory Lane.” Any attempt by me to reproduce that here would not do it justice. The bottom line is, innovation has truly been enabled by the phenomenal advances in technology.

From retrospect comes the compelling need to glance into the future, and, in many cases, the future is now. One can’t look many places today without seeing buzzwords, such as the Industrial Internet of Things (IIoT), big data, Industry 4.0 or Smart Factory. The convergence of information technology (IT) and operational technology (OT) in the IIoT is real, and it is impacting us in a big way. I have to admit, however, that from my perspective on the plant floor it is a software programmer’s key to wealth and prosperity. All that data available to provide valuable insight to the activities on the plant floor is overwhelming without a means to present that data to those who would best use it. My career has long straddled the gulf between IT and OT, and I have been happy to deal with each on its own side of the divide. The melding of the two seems daunting at times as I try to come to terms with how machine and process controls and programming can coexist with this new layer that will talk to the individual devices and carry the health and welfare information to a platform that will monitor and predict future performance. I will be delving more into this in the coming year as I am resolved to no longer maintain this old guy mentality that has held me back thus far.

This stroll down Memory Lane was actually prompted by the quiet retirement of a standard communications protocol, Remote I/O. Universal Remote I/O was developed by Allen-Bradley as a means to connect a processor with one or more remotely located I/O chassis and associated control devices such as ac and dc drives. Originally designed for use with the 1771-based control systems (PLC-2 and PLC-5), Remote I/O has lived a long and prosperous life. This magical blue highway—the cable used for Remote I/O is commonly referred to as “blue hose”—was an easy concept to grasp. Two wires and a shield with termination resistors on each end of the hose pretty much eliminate the possibility of making a mistake in hooking it up. Blue, Shield and Clear on the three terminals of the connector. Universal Remote I/O has a sister protocol, used to connect peer-to-peer communications from one processor to another. Called Data Highway and then Data Highway +, the wiring method also shared the same blue hose but simply inverted the connections with Clear, Shield and Blue to differentiate between the two communications networks.

The retirement of a communications protocol seems like something we should just note in passing, but it caused some ripples in our organization because we did an audit to find out what was still using this standard and were surprised to find some critical parts of our process were using this method of communication. It speaks volumes to the reliability of these controls platforms that they were still running, day in day out, nearly 40 years later. For those who might be interested in what we decided to do, the variable frequency drives (VFDs) in that equipment can use an Ethernet I/P module in place of the Remote I/O, and fortunately the SLC-5/05 processor is already Ethernet, so we do have a stop-gap solution. The prudent choice, of course, is to have a succession plan for the control systems on this equipment because, mechanically, they should still be around for years to come.

The lesson to be learned from all of this is thus: Machinery tends to last longer mechanically than electrically and, even though it might still be running today, it is wise to review these systems periodically to make sure that a retirement of a protocol such as Universal Remote I/O doesn’t leave you suddenly in the lurch if a key component finally breathes its last breath. In most cases, there is something new coming down the technology highway that will make that older system a better candidate for a museum piece.