Sensors and Actuators

For use within control and instrumentation systems, including process control, automative, embedded systems, etc.

"Self validation in process control", by Roger Dettmer, IEE Review, July 2000. An interesting discussion on intelligent sensors that are capable of self-validation.
"A Student's Guide to Sensor Performance Specifications", by Dennis Bernstein to appear in CSM. A basic introduction to sensors, sensitivity and static and calibration response curves.

Thermocouples

http://www.isa.org/journals/intech/feature/1,1773,234,00.html - ISA's InTech magazine review of temperature errors present in cold-junction compensation, by John Houldsworth, including the new, patented method of eliminating cold-junction errors, and an article on temperature measurement accuracy by an end-user. This review is also available as pdf.

Level Sensors

The following links are courtesy of Matthew da Silva (mdasilva@IBD.YAMATAKE.CO.JP)

http://www.lundahl.com/application_notes/dcu1100/bsm.html -- ultrasonic sensor
http://www.deltacnt.com/solids.htm -- mechanically-operated plumb
http://www.levelandflow.com/product/solids/index.html --piezoresistive vibration (but descr. is for granular powders) and microwave
http://www.barton-instruments.com/levelscan_hot.htm -- ultrasonic and others
http://www.chemicalprocessing.com/protected/cp699/equips.html -- microwave radar impulse
http://www.isa.org/journals/intech/brief/1,1772,259,00.html -- microwave impulse radar
http://www.aaliant.com/tank_level/rp9000/rp9000.htm -- microwave impulse radar (dielectric constant greater than 5)
http://www.insatech.com/wf/level4.htm -- microwave impulse radar (dielectric constant greater than 2) but Insatech also has other methods incl. ultrasonic, vibration, electromechanical etc.
http://www.hitechtech.com/ultrasonic.htm -- ultrasonic
http://www.hitechtech.com/soniclas.htm -- sonic laser (manufacturing is Nivelco, a Hungarian firm)

Flow Sensors

pH Sensors