Pick the sensing technique and then pick the integrated circuit (IC) to simplify connecting the sensor in a system. Factory environments frequently use a 4- to 20-mA current loop for transmitting many sensor signals. For some measurements, using a changein capacitance to measure liquid level, pressure, and other parameters provides an inexpensive sensing technique but typically requires complicated signal-conditioning circuitry. Microcontroller-based signal conditioning provides options, including theability to interface pulse, voltage, current, inductive, capacitive, and resistive sensors. New ICs solve each of these sensor-signal-conditioning problems.
Texas Instruments 4- to 20-mA Transmitter
Price: $0.90 ea in quantities of 1,000http://rbi.ims.ca/4912-529Texas Instruments' XTR117 is a high-accuracy, 4- to 20-mA transmitter that operates over a voltage range of 7.5 to 40V with the ability to withstand power surges up to 50V. The precision current-output converter has (±500-µV max offset) and ±4 percent max span errors and provides accurate current-scaling and output-current-limit functions. The unit offers simple over-scale and noise-resistant signaling with 250-µA max power consumption. Packaged in a miniature MSOP-8 and specified for operation over the extended industrial-temperature range, -40 to +125C, the units target pressure, temperature, and humidity-transducer applications, as well as industrial-process monitors.
Analog Devices Capacitance-to-Digital Converter for Capacitive Sensors
Price: $4.60 ea in quantities of 1,000 for AD7745ARUZhttp://rbi.ims.ca/4912-530Designed for floating capacitive sensors, Analog Devices' AD7745/AD7746 are high-resolution, Ó-Ä capacitance-to-digital converters (CDCs). Each channel of the AD7745 or both of the two channels of the AD7746 can be configured as single-ended or differential. Units have 24-bit resolution with no missing codes (up to 21-bit effective resolution), ±0.01 percent linearity, and ±4 fF (factory-calibrated) accuracy. With a variable capacitance input range of ±4 pF, the CDC can accept up to 17 pF of fixed common-mode capacitance, due to compensation by a programmable on-chip, digital-to-capacitance converter. Digital communication occurs over a two-wire, I2C-compatible serial interface. Housed in a 16-lead TSSOP package, the AD7745/AD7746 are specified over the automotive-temperature range of -40 to +125C.
Sensor Platforms Sensor Signal Processor
Price: $3.65 ea in quantities of 1,000http://rbi.ims.ca/4912-531Using a high-speed 8051 processor running at over 14 MIPS, Sensor Platforms SSP1492 can process the signal from a variety of sensor elements and perform powerful vector and scalar calculations. The unit's sensor oscillator, configurable analog switches, and counter-capture unit measure a wide range of resistive, capacitive, inductive, voltage, current, or pulse-mode sensors. The processor's frequency-mode data converter has scalable dynamic range, accuracy, and speed. Digital communication includes either an SPI or I2C serial protocol. The SSP1492 is available as 4-mm-square bare die or in 80-pin land-grid-array (LGA) and micro-leadframe (MLP) packages.
Truchard will be presented the award at the 2014 Golden Mousetrap Awards ceremony during the co-located events Pacific Design & Manufacturing, MD&M West, WestPack, PLASTEC West, Electronics West, ATX West, and AeroCon.
In a bid to boost the viability of lithium-based electric car batteries, a team at Lawrence Berkeley National Laboratory has developed a chemistry that could possibly double an EV’s driving range while cutting its battery cost in half.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.