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The use of radiation thermometers increased 141 percent from 1979 to 1984. This increase is due to the cost-effectiveness of infrared (IR) sensors and the many applications where they can be used. Common applications are quality control, automation and closed-loop process control were noncontact temperature measurement is needed. Improvements in IR sensors have come from four technologies: low-cost optics, stable detectors, microprocessor chip electronics, and packaging. Single sensors are most common, but as costs decrease, more multiple sensor systems are being installed. IR sensors perform well in harsh environments and can measure the temperature of very small objects. They are also capable of measuring the temperature of a continuous line. Included are photographs of IR sensors from Raytek, Vazetti, Ircon and AGEMA, and block diagrams of IR sensor technology and Raytek's ET series sensors.

The HE-33 heat exchanger removes up to 1000W of heat from a sealed cabinet, holding the internal temperature to 24 degrees Fahrenheit above ambient temperature or less. The unit features a closed-loop design, optional special coatings for heat pipes, an aluminum air-inlet filter, and disposable fiberglass filters. The HE-33 ($561) operates at 115V or 230V, 50 to 60 Hz, measures 34.25 by 13.75 by 9 inches, and weighs 70 pounds. A photograph of the unit is included.

Today's microcomputer-based motion control systems can perform many manufacturing tasks that are not possible under manual control, such as rapid and accurate attachment of bond wires on integrated circuit boards. A closed-loop motion control system is necessary where accuracy and response are critical. Compensation is needed in a closed-loop servo system to damp the forces of inertia and to prevent oscillation of the amplifier when the phase shift around the loop apporaches 180 degrees. Motion control systems based on both analog and digital compensation techniques are available. Digital compensation, which is done in software, provides a more flexible servo system that maintains critical damping while operating at or near the optimum performance levels of the motor. Advances in digital motion controller technology will soon lead to the development of devices providing true adaptive control. Block diagrams showing closed-loop servo systems are included.

The schema, its elements and their interrelationships in a liquid pipeline pumping station are discussed. Fixed rather than variable speed pumps are used and control instrumentation is all single function although there are microprocessor controllers which could handle all the functions. Working elements are the pumps and a flow control value downstream. Sensors include a flowmeter and suction pressure transmitter upstream of the pump and a discharge pressure transmitter downstream of the flow control valve. Each sensor feeds its own controller and all controllers feed a highest signal discriminator relay which sends that signal to the flow control valve. In designing the station, consideration must be given to maximum and minimum flow rates, maximum pipeline pressure rating and minimum suction head required by the pumps. A schematic diagram of the pumping station is included.

Low cost and high performance in motor-control circuits can be achieved using audio operational amplifiers. Taking advantage of the circuit's differential input and high current output stages eases the design of servo-motor control circuits. Several circuits are illustrated which implement closed-loop dc-motor speed control. Negative-impedance controllers regulate motor speed without the use of sensors.

The HP-15C programmed in C language, can be used to figure out root locus with the program that is included. The HP-15C will replace the very tedious graphics procedure that relied on a Spirule for finding the root locus. This program used with the HP-15C will also determine the centroid, the asymptote angle, the departure angle from poles, and arrival angle to zeros.

A circuit enables the 567 tone decoder to operate as a lock indicator for the 565 general-purpose phase-locked loop. The circuit combines the sixty per cent hold in range of the 565 with standard features of the 567. The circuit is illustrated.

The testing of switching-mode power supplies is the most difficult phase of their design. Closed-loop testing gives the best results, but the special equipment required for this type of testing is very expensive. The described approach to testing these systems uses a standard current probe and accurately determines stability, switching-transient response, and noise detection. A discussion of the basic design of switching-mode power supplies includes circuit diagrams and provides background knowledge. A circuit diagram that illustrates the interfacing of the test equipment (a wave analyzer and an oscilloscope) to the circuit under test is also provided.

To effectively use the information that intelligent robots are gathering, languages and controllers must be used effectively. These controllers could be combined with sophisticated sensors that can look at the overall situation. Closed-loop control is also necessary to correlate activities with nearby robots. Robots are frequently programmed with a teaching pendant that allows a worker to step a robot through a task. Better ways to program a robot might include off-line programming through a personal computer or by the use of software packages.

National Semiconductor Corp. has a data-separator chip that simplifies disk-drive electronics. The DP 8460 contains functions necessary to perform data-separation on high-density disk drives. There is a circuit diagram of a typical phase-lock loop, and more diagrams on the data-separator organization.