Control Engineering

This question pulls together the entirely unrelated concepts of smart instruments, and predictive maintenance. The smart instruments (sometimes also called “smart sensors”) concept is a hardware-architecture strategy. Predictive maintenance, on the other hand, is a system-level concept.

Smart instruments have been around for a decade or more. The technology falls under the general heading of “embedded systems,” which includes any device containing a microcomputer, but no fully developed user interface. Examples include automotive engine control modules (ECMs); microproce...Read More

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The problem is that hydrogen is simply not a fuel. It is so reactive that it is practically unavailable on Earth in its free form (H₂). It appears naturally only in oxidized form — bound with other elements, such as oxygen (water), carbon (hydrocarbons, such as methane), or both (carbohydrates, such as alcohol), as well as a host of other organic and inorganic compounds of no interest as potential fuels.

It takes energy input to reduce naturally occurring hydrogen to free form, which can then be re-oxidized to get the energy back. H₂, therefore, is an energy storage medium, not an energy source. That fact, of course, is most obvious when looking at electrolysis. 

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There are two issues to face when choosing a system integrator for a mechatronics project: how much of the project to keep in house, what to contract out, and how to keep control of the project. If this sounds like Project Management 101, it is.

The minute you decide to do any development involving a third party, you’re playing in the project-management sandbox — and that box is always filled with quicksand. Whether you sink or swim depends on how carefully you approach it.

Before even thinking about looking for a contractor, you need to think about why you need him/her/them. The only reason to look outside your company is to fill a hole in your company’s capabilities.

Every company, of course, has holes in its capabilities. Companies should have internal resources to cover their core competencies, but not be loaded with e...Read More

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The Hall effect, is a magnetohydrodynamic phenomenon where an external magnetic field affects the flow of charge carriers in a semiconductor in such a way that an electric field appears directed at right angles to both the magnetic flux lines and the current-flow direction.

Magnetohydrodynamics (MHD) is the study of electrically conducting fluids in motion. In this case, the electrically conducting fluid is the ensemble of majority charge carriers in the semiconductor.

For example, in P-type semiconductor material the majority charge carriers are positively-charged holes. A Hall sensor could be made from a rectangular t...Read More

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Analog to digital converters (ADCs) are arguably the most common mixed signal circuit in use today. The successive approximation register (SAR) type is potentially the most accurate ADC circuit, although it is not the fastest.

ADCs accept an analog voltage as input and provide a digital bit pattern as output. The digital bit pattern represents the value of the input after preparation by the measurement system. Preparation steps include signal conditioning, amplification, and quantization (sampling).

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Machine vision is not a discipline in itself, such as mechanical engineering. It is a skill involving specialized equipment. How you should go about gaining that skill depends on your goals.

If you simply want to gain proficiency with specific equipment in your shop (as is the case with the person who sent in this question), the best place to start is with the manufacturer of that equipment. Virtually all vision-system suppliers provide excellent user manuals and similar documentation in printed and online form. Some, such as Cognex and Dalsa also provide tutorial...Read More

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Mathematically, a pole is any geometric singularity. For example, the Earth’s north and south poles are places where lines of longitude meet in singularities. In other words, the longitudes of these poles are undefined. Actual, physical poles don't seem to exist. Black holes are theoretical singularities, but are saved by having an event horizon. (They may be singularities, but not in this Universe!) Electrons are saved from being singularities by wave-particle duality.

In electromagnetism, the term “pole” refers to a point where field lines meet. Electric field lines, for example, meet at point charges. One point charge is called a monopole. Two charges form a dipole. Three form a tripole, and so forth. Of course, real charges are spread out over the surfaces of physical objects, so they aren't really singularities.

Magnetic ...Read More

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Digital filters capitalize on the fact that digital electronics looks at waveforms as a timed sequence of values, rather than instantaneous voltages. Digital filters start with an analog waveform, convert it to a digital waveform, perform operations on the digital values, then convert the waveform back to an analog waveform.

The figure below shows the steps in this process. The analog waveform is a time-varying voltage called the baseband signal. Passing this baseband signal through an analog-to-digital convertor (ADC) changes it to a series of voltage measurements, which are stored as an ordered set of numbers with a time interval associated with each. A digital signal processor (DSP), which may be an ASIC, FPGA, or even a fast microprocessor, performs a Fourier transform on the data streaming in. This changes it from a series of numbers associated with time intervals t...Read More

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I mentioned chemistry as being important to a mechatronics engineer working on environmental projects in my June 9, 2008 blog entry, and for most such projects that would be true. The thing to keep in mind is that mechatronics engineering integrates development projects at a very high level. Traditional engineering disciplines focus on the piece of equipment being developed.

An electronics engineer working on an audio amplifier, for example, works from specifications that involve electronics quantities, such as input signal level, frequency bandwidth, and so forth. It makes little difference what application that amplifier ends up in. I have seen high end stereo amplifiers that were designed for consumer high fidelity market used quite ...Read More

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The other day, Control Engineering process industries editor Pete Welander and I were talking about the evolution of various standards on the way out to the parking lot, when this week’s question came up. We couldn’t remember quite when RCA connectors, one of several competing standards for interconnecting audio equipment, appeared.

RCA connectors are those neat little color-coded plugs found on stereo equipment, public address (PA) systems, and high-end televisions. They’ve been around so long most of us take them for granted, but few of us remember when they first appeared. 
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Mechatronics is a cross-disciplinary system-level discipline. So, a mechatronics engineer needs a very broad technical background as well as communication and interpersonal skills.

The term system-level gets bandied about a lot, but I’m not too sure how many engineers have a good working definition of it. I came across my favorite definition long, long ago in a galaxy far, far away during a brief stint as a business systems analyst at Dupont. I snagged a book out of the department library, which I remember being Fundamentals of Systems Analysis by Jerry Fitzgerald.

The definition (as I remember it) took a Zen approach by explaining what systems weren’t. It pointed out...Read More

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Anyone who has actually put an operating laptop computer on top of their lap knows why cooling is important for any computer. Microprocessors dissipate a lot of electric power, which turns into heat, which must be removed somehow. They do this despite the fact that the metal-oxide-semiconductor (MOS) field effect transistors (FETs) making up the bulk of the computer circuitry are theoretically very efficient when operating in switched mode (saturated on or cut off).

MOSFETs are effectively voltage-variable resistors. A voltage ...Read More

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