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 […]
Using optical fibers for temperature measurement, Part 1: Context
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 […]
Undersea optical-fiber cables do double-duty as seismic sensors, Part 1: Context
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 […]
ICs for interfacing inductive sensors, Part 2
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 […]
ICs for interfacing inductive sensors, Part 1
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 the two preceding features (see Related EEWorld Content), we looked at the inductive proximity sensor and its basic operation but did not look at the electronic interface circuit for this widely […]
What are inductive proximity sensors, Part 2
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 […]
What are inductive proximity sensors? Part 1
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, […]
LVDT electronics, Part 2: interface circuitry
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 […]
LVDT electronics, Part 1: excitation and demodulation
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 […]
Kelvin 4-Wire sensing solves the “IR Drop” problem
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 […]