As a kid growing up in a town of 1,000 population, with the nearest larger town over 120 miles distant, in the coffee-shop next to my Dad’s two-pump service station was a small card taped to the cash register which read,
“A friend is not a fellow who is taken in by sham,
A friend is one who knows your faults and doesn’t give a damn.”
In that small town we knew everyone, faults and all, and it made a lot of sense. Steve may have been stepping out on his wife, but we could depend on him if help were ever needed. I felt we had plenty of friends. However, Dad told me I’d be happy to count my true friends on one hand. My perspective of that “friend” quote did change when I had my own children. I gave more than a damn how they turned out.
I served two years in the U.S. Army at White Sands Missile Range on the Redstone Missile program. We were engaged in the high-tension space-race, leading to Russian cosmonaut Yuri Gagarin’s first man-in-space event in April 1961, completing one full orbit of the earth.
Fig. 3.1 Yuri Gagarin – Russia’s first man-in-space and the 43 meter titanium monument erected in his honor in Moscow.
Gagarin became the first human to travel into space. During his 89 minute flight, he orbited the Earth at an altitude of 187 miles, guided entirely by an automatic control system. The only statement attributed to Gagarin during his one hour and 48 minutes in space was, “Flight is proceeding normally; I am well.”
After his historic feat, Gagarin became an instant world-wide celebrity. He was given the title of “Hero of the Soviet Union.” Monuments were raised across the Soviet Union and streets renamed in his honor.
The triumph of the Soviet space program, putting the first man into space, was a great blow to the United States. Gagarin had orbited the Earth, a feat that eluded the U.S. space program until February 1962, when astronaut John Glenn made three orbits in Friendship-7. I also remember the concern we all felt when the Soviets launched the first satellite into space in 1957, the Sputnik. Gagarin was killed in a routine jet-aircraft test flight in 1968 near Moscow. His ashes were placed in the Kremlin wall.
Following the Army service I married my sweetheart, then struggled through the university, earning a BS in Electrical Engineering. My first job out of school was in the city of Milwaukee with AC Spark Plug, division of General Motors, on the Titan missile program. This was the heyday of “Sputnik” fervor. Kennedy had declared war on the lack of scientific minds. It was an interesting time in international politics.
While working at AC I met a teacher who encouraged me to apply for a night-school position at his vocational school. I did, entered my first teaching experience with stage-fright, but hung on, coming to love the effort. Later, when a full-time position opened I left industry and spent five years teaching instrumentation. It was a strange turn, having just received a commendation from General Motors for work on a Titan missile guidance & control package. But I had found a niche in the classroom.
Instrumentation is the measurement and control of industrial processes. The idea is to measure some variable (pressure, temperature, flow, force, humidity, etc.), compare the measurement with the desired (target) value, and make corrections to move the variable to the target.
Fig. 3.2 Physical Control Block Diagram
The sensor (Controlled Variable) is transmitted to the Controller where the actual temperature is compared to the Set Point (the desired value).
Any difference between the two sends a corrective signal to manipulate the Final Control Element, bringing the process temp to the Set Point.
This scheme works for any process requiring control! If you want to control the temperature in your home at 70 degrees, you’ll encounter multiple disturbances, from outside temperature changes to the kids leaving a window open.
The control loop in your home will take care of that, with the thermostat turning the furnace on and off at the set-point.
Fig. 3.3 There are thousands of instrumentation loops in an operation like this, dozens in your home and/or automobile.