Twenty five years ago, Eric and Evan Campbell built the first Campbell Scientific product - a space averaging anemometer. It was a fascinating sensor. A laser was used as the light source for the anemometer located several hundred metres away. Air mass movement across the light path was measured by correlating the scintillation pattern in the light to the average wind speed across the light path._x000D_
I remember joining the company in 1975, just prior to an anemometer being prepared for delivery. The customer who ordered the anemometer had arranged to visit our office in Logan to observe the instrument in operation. We set it up along the shoulder of a highway on a sunny August day. At first our customer was skeptical. We turned the sensor upside-down and showed that the output was of the same magnitude but of opposite polarity. We showed that the output went to zero when the light path was blocked. We then visually observed the mirage effect along the highway in which we could "see" the wind blowing across the highway, and we were able to draw a correlation between this visual effect and the output of the instrument. At last he was convinced._x000D_
There were many who contributed to the successes of the company over the last 25 years, but I must surely acknowledge the singular contributions of Eric Campbell who led the company from 1974 until just prior to his death in 1992. During 1975, in search of a larger market, Eric and Evan began designing more general purpose field data acquisition instruments. With the advent of the microprocessor in the 1970s, Campbell Scientific was one of the first companies to offer low-power, high-precision, field data loggers. In addition to guiding the philosophy of the company, one of Eric’s great contributions was the unique combination of digital, analog, and operating system design attributes which were the foundation for many of the company’s products during the first 20 years._x000D_
Another aspect of Campbell Scientific’s progress has been integrating our field data loggers into sophisticated measurement systems. Bert Tanner joined the company in 1978 and has served as our Vice President of Marketing and Customer Service since 1980. Bert’s philosophical contribution has influenced the manner in which the company is represented to you, the customer. In addition, he has made significant technical contributions to integrated measurement systems ranging from automatic weather stations to boundary layer gas exchange and turbulent transport measurements._x000D_
Over the last 25 years there have been interesting changes in the technology used in field data acquisition systems. We started out using discrete logic with fairly simple, low power integrated circuits to accomplish timing for scan intervals, average multiple readings over an output interval, etc. With microprocessors, these functions are now designed mostly in the operating system firmware, causing a fundamental change in our products toward the increased use of digital processing and more sophisticated operating systems._x000D_
Changes in technology have enabled us to design and deliver increasingly sophisticated instruments in smaller packages. When we started, all parts were soldered by hand into circuit boards that had traces only on one side of the circuit board. Then we began using circuit boards with traces on both sides and plating in the holes. Now circuit boards have multiple layers with surface mount components. Components may even be mounted on both sides of a circuit board. Some components we use are very sophisticated with links "burned" (programmable arrays) to determine logic function._x000D_
Some things have changed in the nature of your work during the last 25 years as well. Because it is easier to do so, you probably make more field measurements. You may have an automated means of data collection with the convenience of telemetry. You probably have a computer on your desk or in your lab where you carry out analysis and report results._x000D_
Campbell Scientific would not be celebrating a 25th Anniversary without you, our customers. I hope that the success of your work is enhanced by Campbell Scientific’s products and services. May the next 25 years continue to be mutually rewarding.