Sensing advances: infrared absorption, handheld electrochemical, mass gas flow

Within the control loop-sense, decide, actuate-sensing always gets top billing. Recently discussed sensing technologies include infrared-absorption-based sensor for CH4, H20, CO, HCN, and CO2; handheld electrochemical sensor; advanced thermal mass gas flow control; temperature, strain, tilt, vibration, corrosion, humidity sensors; and a single-chip pressure sensor.

By Control Engineering Staff December 17, 2003

Within the control loop-sense, decide, actuate-sensing always gets top billing. Recently discussed sensing technologies include infrared-absorption-based sensor for CH4, H20, CO, HCN, and CO2; handheld electrochemical sensor; advanced thermal mass gas flow control; temperature, strain, tilt, vibration, corrosion, humidity sensors; and a single-chip pressure sensor.

Ion Optics Inc . is working on the SensorChip, an infrared-absorption-based sensor for CH4, H20, CO, HCN, and CO 2 , for use in a respiration monitor. Other applications include leak detection and ventilation.

MesoSystems is working on a handheld electrochemical senso r in a microfluidics cartridge. Different organisms filtered have different nanoAmp readings. Target preparation time for the sample is under a minute and analysis target 30-35 minutes, at a cost per test of $5-10 each. Working range is 500 cells to 100 million cells per ml. Prototypes have been made and used.

Redwood Microsystems offers the Dual Purged MFC (mass flow controller) Model 9900.

Redwood Microsystems Inc . is working on advanced thermal mass gas flow control using MEMS components. After die development time of two years, capabilities are 80:1 dynamic range, 1% of setpoint accuracy, under 250 milliseconds response time, and ability to vary capabilities. Unlike previous sensors, this one provides nonlinear response, providing higher accuracy at lower pressures. As the pressure increases, the amount of capacitance decreases, as the silicon becomes stiffer. Present product is called Dual Purged MFC (mass flow controller). This is a dual-purge gas stick with four SOVs, two pressure sensors, and an MFC. Smaller than a thermal MFC, the dimensions are: 1.125 x 2.6 x 4.8 in.

Senera Corp . targets infrastructure monitoring (bridges primarily) by considering temperature, strain, tilt, vibration, corrosion, humidity , and communicating information, increasingly via a wireless mesh network .

Silicon Microstructures Inc . offers a low-cost Single-Chip Amplified Pressure Sensor . The ASIC structure lowers cost, size, creates higher reliability, reduces number of connections, has ability to add capability with a dedicated signal processor and integration of added components on the chip. Chip operates at 5V for analog and digital components. SOIC-16 package sensor has an open area for a pressure diaphragm. Cost per chip is under $2.

One option to help tie it all together is Arecont Systems Inc .’s Kontar KM800 Internet-based control system . It offers distributed control via the Internet and a browser. The structure can save considerable money in retrofitting older automation projects, where new wiring, up to half the cost of a retrofit, is difficult to run, according to the company.

This information was presented at Sensors Expo, in Anaheim, CA, in September 2003.

For related items see:

  • A Wider Field of View

  • Think Again: How to improve techno-business

  • Sensors Expo Fall 2003: Sense the world through online eyes

—Mark Hoske, Editor-in-Chief, Control Engineering, MHoske@cfemedia.com