When it comes to nearly all biological measurements, the ranges of many of the parameters of interest are orders-of-magnitude below those with which many engineers are familiar. Instead of megahertz or even kilohertz, the living-creature world is in the single or double-digit hertz range, such as the roughly 60+ beats per minute (BPM) for a […]

Among the many ways to sense temperature, combinations of advanced optical principles used with optical fibers offer very different approaches, with application advantages and implementation limitations. The previous part of this article looked at two approaches to using optical fibers for temperature sensing based on the fiber Bragg grating (FBG) and the Mach-Zehnder interferometer (MZI). […]

Among the many ways to sense temperature, combinations of advanced optical principles used with optical fibers offer very different approaches, with application advantages but also implementation limitations. The first part of this article discussed general issues of sensing of physical parameters, especially temperature, and total internal reflection in optical fibers. This section will look at […]

Among the many ways to sense temperature, combinations of advanced optical principles used with optical fibers offer very different approaches, with application advantages and implementation limitations. Temperature is the most widely sensed physical parameter; it’s that simple. What’s not simple is the many ways we have of measuring it through the use of sensors such […]

A research team has devised and tested a scheme based on advanced optical-physics principles which uses active submarine optical-fiber data cables to also sense ocean-floor earthquakes and ocean-surface swells. Sensing of physical parameters such as temperature, pressure, force, and velocity often brings a “split personality” analysis. On one hand, getting a reading of the basic […]

Designers who use inductive proximity sensors have a choice of high-performance signal-conditioning interface ICs, each offering different sets of features, functions, and capabilities. The first part of this article discussed some of the sensing opportunities and looked at an IC from Texas Instruments. This part looks at ICs from Renesas and Microchip Technology. Renesas IPS2550 […]

Designers who use inductive proximity sensors have a choice of high-performance signal-conditioning interface ICs, each offering different sets of features, functions, and capabilities. In two predecessor features (see References), we looked at the inductive proximity sensor and its basic operation (see References) but did not look at the electronic interface circuit for this widely used […]

Non-contact sensing of a nearby object’s linear or rotary position in an electrically and mechanically harsh environment is a common system requirement. There are several ways to meet this objective, including sensors based on the Hall effect, the magnetorestrictive effect, and magnetic coupling. One widely used approach is inductive proximity sensing, which is effective, accurate, […]

The first part of this article introduced the inductive proximity sensor. This second and final part looks at some more specifics of this sensor. Q: Are there different architectures and implementations? A: Yes, there are three basic types: 1) the magnetic elements alone are in the sensor. This separates the electronics from the sensing coils […]

For applications driven by sensors more than high-speed data, the IEEE 802.3cg standard offers single-pair Ethernet connectivity with far lower cable costs and bulk. Part 1 looked at the context and standard which defines Single-Pair Ethernet and some of its variations, and how it fits into the IIoT application area. This part will look at […]

The interface electronics for the LVDT must excite the primary-side winding with a sine wave and then demodulate the two resultant secondary-side waveforms; modern ICs make this analog-signal process fairly straightforward. Part 1 of this FAQ looked at the basics of LVDT excitation, demodulation, and waveforms. This part looks at two standard ICs which implement […]

The interface electronics for the LVDT must excite the primary-side winding with a sine wave and then demodulate the two resultant secondary-side waveforms; modern ICs make this analog-signal process fairly straightforward. The first two parts of this LVDT article (see References) looked at the LVDT transducer itself, along with its attributes and history. This second […]

Novice engineers usually don’t learn about this problem and its solution in school, but “practicing” ones learn about it soon enough! Problem: I need to determine the change in resistance of a low-resistance sensor located many meters away. My plan was simply to apply a known voltage across the thin-wire sensor leads and measure the […]

The linear variable differential transformer (LVDT) is a widely used, inherently rugged, linear-position sensor offering accurate and consistent performance over a wide span of distances. Part 1 of this FAQ looked at the basic operation of the LVDT. This part looks at some of its other performance attributes and characteristics. Q: What does an LVDT […]

The linear variable differential transformer (LVDT) is a widely used, inherently rugged, linear-position sensor offering accurate and consistent performance over a wide span of distances. Sensing of physical position is among the most commonly needed parameters in industrial, military/aerospace, robotics, scientific measurement, and control applications, and there are many sensors in use to accomplish this. […]