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Creating a Homebrew Industrial Process Monitor?
pionzypherm asks: "I work at a glass plant for a major beer company. My job entails monitoring the furnaces that melt the glass. I have been working on a project on the side, collecting data from various sources and compiling it into an easily used form for the higher ups. I've finished two of our three furnaces, but one remains. This furnace uses technology from the early nineties. There is no networking, the hardware is completely closed and unavailable for any screen scraping. Two of the items I'm looking to monitor (and would appear to be the easiest starting point) are two valves for a gas and oxygen line which will provide data on a portion of our energy usage. I was thinking of a microcontroller board or something similar tied in to monitor the positions of the valves. I'm unsure where to begin though. What books, microcontroller boards or alternatives would you recommend for someone new to this? What suggestions would you have for such a project, and what pitfalls might I run into?"
...let's be clear about this: all you're doing is monitoring and gathering data - there is to be no feedback signal from the homebrew rig to control the valves. There's a whole field devoted to control theory, one that is best not trifled with, especially with industrial processes that can potentially cause fatalities.
If you really want meaningful data from those process streams, you're much better off installing calibratable (calibrable?) flowmeters on those lines that cover the performance range of the process fluids you're working with. If you've got the flow, you don't need the valve position, unless it's for a secondary indication to validate the valve's performance (e.g., position vs. Cv vs. measured flowrate). The flowmeters can be hooked up to provide data for remote collection, or more simply, display data for periodic local reading. Here's a mess to start with. Whomever you buy from, you'll need to develop specifications defining the operating range, operating conditions (pressure, temperature, humidity), power requirements, tolerances, calibration frequency, etc.
Science never settles, never rests.
I build CNC and automation equipment, so I can pretty safely say that from what you describe this is a brain-squishingly trivial project. Probably one that can be done over lunch - After you spend five years climbing the learning curve, which is not at all trivial.
I would just ask someone who does do this for a living out for lunch, it'll take them ten minutes. I do this when I need coding done. The price of a few beers to get the occasional patch or script written is a lot more efficient than many years learning coding to do it myself the one time a year the need comes up.
The learning curve on automation hardware is at least as steep as learning Linux, and with crappier documentation. Coding guys usually seem to underestimate the complexity of the physical engineering and design side, and think they are always bright enough to just pick it up and do our jobs. There is more to hardware engineering than the butt-crack guy with a monkeywrench, just like there is more to coding than script kiddies.
In short - unless you want to go into this as a hobby or career change, just treat a hungry engineer to lunch and call it good. Even if you paid him it'd be less than the books you'd need.
Every time someone asks Slashdot a question like this, the hysteria crowd comes out of the woodwork to scream about how it's absolutely impossible for an "amateur" to do it, and you absolutely must hire a "professional," lest something tragic happen, ranging from the ever-popular "you'll lose your job!" to a bucket of dead puppies or something.
Yes, I realize that professionals are sometimes necessary, especially in situations where life is clearly at stake (pilots, medical, law, etc.) I'm sure some jackass will show up to tell me how this is an industrial furnace and that clearly means that a professional is warranted, but we have no idea what the particulars of this situation are. Just stick to the freakin' question, people.
It used to be the case that "professional" implied not only a degree of competence, but also a certain amount of integrity and experience. But that's just not true any more. All it means now is that someone gets a paycheck for doing something. Often it means that they're experts in nothing more than doing something as cheaply as possible.
For what it's worth, I'm personally fond of the Atmel AVR microcontrollers. Many, many people are also fond of Microchip's offerings in the PIC line. But for rapid development, something like the Parallax BASIC Stamp is probably the way to go. They're cheap and easy (like a good woman) and let you focus on the task at hand rather than the bit-level details of how to read sensors, etc.