Showing papers in "IEEE Transactions on Industrial Electronics and Control Instrumentation in 1969"
TL;DR: In this article, a digital pressure transducer was developed utilizing a precision 5 MHz piezoelectric quartz resonator, which exhibits linear changes in frequency when subjected to radial compressive stresses.
Abstract: A digital pressure transducer has been developed utilizing a precision 5 MHz piezoelectric quartz resonator. The circular resonator exhibits linear changes in frequency when subjected to radial compressive stresses. A cylindrical quartz tube, integral with the circular resonator, acts as a diaphragm and transfers and concentrates the stress from the applied pressure onto the periphery of the resonator. Since the tube and resonator are fabricated from a single quartz crystal, nonelastic effects are minimized. The transducer has a dynamic range of 107and a pressure range of 0 to 104psia.
140 citations
TL;DR: In this article, a mathematical model of the permanent magnet stepping motor is developed and experimentally verified for a single step response and linearized equations which allow the motor to be expressed in terms of a damping ratio and natural frequency are developed.
Abstract: A mathematical model of the permanent magnet stepping motor is developed and experimentally verified. Linearized equations which allow the motor to be expressed in terms of a damping ratio and natural frequency are developed for a single step response. Multistep motor operation, when driven by a current source, is analyzed using phase plane techniques. Failure of a stepping motor to follow a fixed stepping rate command is analyzed. Dimensionless curves showing maximum stepping rate as a function of motor parameters and applied load torque are derived and experimentally verified.
31 citations
31 citations
TL;DR: A method is presented for increasing the accuracy of position and velocity detecting systems which make use of pattern recognition principles due to the binary nature of receptor elements which causes the receptor to have a nonlinear transfer characteristic.
Abstract: A method is presented for increasing the accuracy of position and velocity detecting systems which make use of pattern recognition principles. The basic limitation of these systems is due to the binary nature of receptor elements which causes the receptor to have a nonlinear transfer characteristic.
28 citations
TL;DR: In this paper, the rationale behind the development of a capacitive-type sensor along with the functional and electrical characteristics to encourage confidence in the basic mechanism is presented along with a detailed description of the sensor mechanism.
Abstract: Of all the basic environmental variables, only humidity has resisted simple, reliable measurement. Hygrometric elements have always had limitations in their useful application, especially with regard to their inability to be stable and durable. Here, the rationale behind the development of a capacitive-type sensor is presented along with the functional and electrical characteristics to encourage confidence in the basic mechanism.
22 citations
TL;DR: In this paper, the use of the laser-acoustic interaction has been shown to be among the most promising approaches for obtaining a continuously variable delay for RF and microwave signal processing.
Abstract: The variable delay and processing of RF and microwave signals is a current problem of considerable importance both for the many military applications in radar and electronic counter-measures and for the civilian applications in signal processing. The very low velocity of acoustic waves, as compared to the propagation velocity of electromagnetic signals, permits the fabrication of physically compact systems capable of storing and processing electromagnetic signals. Among the several suggestions for obtaining a continuously variable delay, the use of the laser-acoustic interaction has been shown to be among the most promising.
11 citations
TL;DR: In this paper, a feedback system designed to control the surface temperature of a metallic body immersed in a boiling liquid is described, which is inherently unstable in one of its three regions of operation, but under automatic feedback control, stable and precise operation is obtained in all regions.
Abstract: This paper describes a feedback system designed to control the surface temperature of a metallic body immersed in a boiling liquid. The process is inherently unstable in one of its three regions of operation; however, under automatic feedback control, stable and precise operation is obtained in all regions. The surface temperature can be accurately maintained at any desired steadystate level in any region of process operation, and sine-wave or transient variations in temperature can be obtained when the system is driven from an electrical signal generator.
9 citations
TL;DR: In this article, the authors present a new phaseplane display that provides useful conceptual insights into the performance of common thermal processes, such as fluid heaters, heat treatment plants, boilers, dryers, vats, etc.
Abstract: Common thermal processes, such as fluid heaters, heat-treatment plant, boilers, dryers, vats, etc., can conveniently be modeled by first-order transit-delayed equations. These processes are widely used in industry where they are usually discontinuously controlled by on-off or on-half-off controllers. Often the heating rates and cooling rates of such processes differ significantly. This hinders the evaluation of their performance indices, yet the accurate evaluation or prediction of these performance indices is an important step in the design (or selection) of controllers for such processes. This paper presents a new, yet simple, analysis of the mode-dependent performance indices of these controlled processes. New phaseplane displays are presented that provide useful conceptual insights into their startup, shutdown, and limit-cycling performance. This paper is intended for the professional engineer engaged in the design and control of these processes, and the presentation is practical rather than mathematical.
7 citations
TL;DR: In this article, a bridge circuit was designed to perform a comparison between a temperature which is the controlled variable in a feedback control system, and a reference input or set point value.
Abstract: This paper describes a bridge circuit which was designed to perform a comparison between a temperature which is the controlled variable in a feedback control system, and a reference input or set point value. The feedback system was designed to control a certain heat transfer process.
6 citations
TL;DR: An approach to the mechanization of an analog electrical-to-fluidic transducer using carrier circuit techniques is described in this paper, along with a laboratory breadboard model along with test results.
Abstract: An approach to the mechanization of an analog electrical-to-fluidic transducer using carrier circuit techniques is described Design details for a laboratory breadboard model are given along with test results Mechanical design is based on the use of a bender-type piezoelectric assembly, driven by dc voltage controlled microelectronic oscillators Several questions, regarding feasibility of the approach such as size of the transducer, electrical input voltage level, and electrical power level are resolved favorably by the results of breadboard model testing Consideration is given to inclusion of an inverted acoustic horn for signal intensification
4 citations
TL;DR: In this paper, three papers have been published on the on-off control of temperature in industrial processes and they reported results that appeared to conflict, and this subsequently caused confusion in industrial control circles.
Abstract: Recently (1967-69) three papers have been published on the on-off control of temperature in industrial processes. They reported results that appeared to conflict, and this subsequently caused confusion in industrial control circles. This paper critically examines these papers and shows that two are complementary while the third is misleading. New results are reported that cover deficiencies in all three papers. The presentation is intended for the professional engineer concerned with the control of industrial plant, rather than the control scientist.
TL;DR: The fundamental problem in applying fuses for the protection of semiconductor devices is that of ensuring that the fault energy let-through of the fuse comes within the withstand of the device under the circumstances in which both are used in service.
Abstract: The fundamental problem in applying fuses for the protection of semiconductor devices is that of ensuring that the fault energy let-through of the fuse comes within the withstand of the device under the circumstances in which both are used in service. Great progress has been made during the last few years towards this end but more study is urgently needed.
TL;DR: In this article, a sensitive and efficient piezoresistive element is described, which is constructed of p-type silicon mounted on an electro-mechanical substrate, and thus is easy to handle and apply where the measurand can be reduced to a force of about 10 grams.
Abstract: A sensitive and efficient piezoresistive element is described. It is constructed of p-type silicon mounted on an electro-mechanical substrate, and thus is easy to handle and apply where the measurand can be reduced to a force of about 10 grams. This device, the PIXIE, is linear, low noise, relatively inexpensive, and can stand large overloads.
TL;DR: After discussing computer language successes and failures, the job of applying a computer to a process and the effect of language on this is considered and the conclusion is made that a single standard language is unlikely.
Abstract: After discussing computer language successes and failures, the job of applying a computer to a process and the effect of language on this is considered. A review of the characteristics that a language should have, with particular attention to the kinds of programmers involved in process control computing, is presented. Next, a new, nonalogrithmic approach to programming is described and finally, the conclusion is made that a single standard language is unlikely.
TL;DR: In this paper, a resistance wire temperature sensor is used to measure the environmental temperature, and it is essential that the current required in the sensing circuitry does not cause excessive heating of the sensing element.
Abstract: In many control or instrumentation circuits, a resistance wire temperature sensor is often used to measure the environmental temperature. Because the sensor current itself can change the resistance of the sensor, it is essential that the current required in the sensing circuitry does not cause excessive heating of the sensing element. The power loss caused by any current in the resistance sensor will always produce some change in resistance; a specific value for self-heating current is meaningful only when related to a specified percent deviation from the zero current resistance.
TL;DR: In this paper, the authors explore the range of instrumentation techniques available and focus particular attention on a conductivity technique employed in measuring dew point temperatures, and present a general survey of present applications, as well as a discussion of possible future applications.
Abstract: Moisture control is recognized to be an exceedingly important process control variable, especially when compared to advances in measurement and control of other process variables. This paper explores the range of instrumentation techniques available and focuses particular attention on a conductivity technique employed in measuring dew point temperatures. A background of investigative efforts in moisture film formation is given and the development of a dew temperature transducer from this basic work is described. A general survey of present applications is presented, as well as a discussion of possible future applications.
TL;DR: In this paper, a magnetic means is employed to compare the hardness of a given material to a sample of the same material of known hardness, and test results are presented for carbon steel and alloy steel.
Abstract: A number of researchers have reported work of varying degrees of success in determining mechanical hardness by magnetic means. The methods reported fall into the two categories of static testing (dc) or dynamic testing (ac). This paper describes a method of testing which is named the "differential" method. Since mechanical hardness is affected by many factors, several of which have no effect on magnetic properties, a universal hardness tester operating on magnetic properties would be impossible to develop; however, this paper describes how a magnetic means is employed to compare the hardness of a given material to a sample of the same material of known hardness. Test results are presented for carbon steel (AISI 1095) and alloy steel (AISI 4150).
TL;DR: In this article, an alternative method for determining the angular position of a rotating shaft is introduced, where the required information is obtained from the envelopes of a modulated carrier at the stator terminals of an ac servomechanism.
Abstract: An alternative method for determining the angular position of a rotating shaft is introduced. The required information is obtained from the envelopes of a modulated carrier at the stator terminals of an ac servomechanism. Essentially, a single-phase constant amplitude carrier signal is applied to the rotor winding; with zero stator current, the amplitude of the transformed carrier at any stator winding depends on the cosine of the angle between the rotor and stator windings, provided the ratio of rotor speed to carrier frequency is small. The stator envelopes may be decoded by analog methods to give a single analog signal calibrated to indicate the shaft position within a 360° range. An example of the application of this method to static drives for ac machines is included.
TL;DR: In this paper, an X-band reflex klystron is modified for a highly sensitive pickup sensor for an accelerometer and a seismometer application, with a potential accelerometer sensitivity of 2 μg indicated.
Abstract: An X-band reflex klystron is modified for a highly sensitive pickup sensor for an accelerometer and a seismometer application. Seismometer sensitivity of 460 μJ are recorded with potential accelerometer sensitivity of 2 μg indicated in this preliminary test.
TL;DR: In this paper, the Maxwell commutated dc bridge is analyzed, physically and mathematically, and it is shown to have advantages as signal processing circuit capable of reflecting the value of a capacitive transducer in proportional values of an active variable, current or voltage, and of providing indication or doing work.
Abstract: The Maxwell commutated dc bridge is analyzed, physically and mathematically. It is shown to have advantages as a signal processing circuit capable of reflecting the value of a capacitive transducer in proportional values of an active variable, current or voltage, and of providing indication or doing work. In particular, the circuit is shown to be applicable to capacitive unknowns having significant, finite series or parallel resistances; this contrasts with the contention of the classical references on the circuit. Also, the formerly widely used driven switch mechanism is replaced by a crystal-oscillator-driven solid-state switch, thus enhancing the reliability of the system. Experimental results for a representative circuit with both ideal and lossy capacitive unknowns conclude the paper.
TL;DR: In this paper, the use of a dc meter and four diode rectifiers is used to measure resistance of electrolytic conductivity cells where asymmetric polarization is to be avoided.
Abstract: Variations of a current-difference circuit for making impedance measurements were investigated theoretically and several modifications were tested. The circuit is based on the use of a dc meter and four diode rectifiers. It can compare two impedances, while maintaining alternating current flow through both impedances. The latter characteristic makes the circuit applicable to the measurement of resistance of electrolytic conductivity cells where asymmetric polarization is to be avoided. The comparison is not inherently dependent on a ratio established by a pair of resistors or by a pair of transformer windings. The circuit can compare impedances of similar phase angle, for example, two resistors, two inductors, or two capacitors. It can also compare impedances or admittances of different phase angle. This latter characteristic is of value, for example, in the measurement of the resistance component of electrolytic conductivity cells where there may be a small series reactance component as the result of symmetrical polarization. The precision of this simple circuit appears satisfactory for many practical applications of electrolytic conductivity measurement. The utility of the circuit is based to a large extent on the good characteristics of diodes now available.
Journal Article•
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TL;DR: In this paper, the basic principles of fluid resistance thermometers are briefly stated, and the principles of the fluid oscillator types of temperature sensors are discussed in detail, including the physical phenomena making an oscillator temperature-sensitive.
Abstract: The basic principles of fluid resistance thermometers are briefly stated, and the principles of the fluid oscillator types of temperature sensors are discussed in detail. The physical phenomena making an oscillator temperature-sensitive are covered including the edgetone effect and edgetone cavity coupling. It is pointed out that choked flow is required if the same modes of edgetone and cavity frequencies are to remain coupled over a large temperature range. Very fortunately this same condition (choked flow) makes the oscillator pressure insensitive.
TL;DR: Man has used models since prehistoric times to represent various aspects and functions of his known and even of his unknown environment to match specific needs and chooses between various analogies in different media-including that of purely mathematical formulation.
Abstract: Man has used models since prehistoric times to represent various aspects and functions of his known and even of his unknown environment. He appears to need these models as conceptual crystallization centers, to adjust himself to his environment and as tools to control it. In learning, he readjusts the structure and detail of these models to match specific needs and chooses between various analogies in different media-including that of purely mathematical formulation. For control purposes, he predicts on the basis of such model behavior the probable effects of any control and chooses the mode and magnitude of his actions. This paper covers recent developments in this field of control.
TL;DR: In this paper, a new facile technique for readily determining the boundary conditions for stability when selecting controllers or locating transducers is presented, intended for the professional engineer engaged in the control of boilers and liquid-heating processes in industry.
Abstract: It is well known that common boilers and similar thermal processes for the bulk heating of liquids can become unstable, when closed-loop controlled, if the controller and/or the controlled-variable transducer location are chosen arbitrarilly. This paper describes a new facile technique for readily determining the boundary conditions for stability when selecting controllers or locating transducers. The presentation is intended for the professional engineer engaged in the control of boilers and liquid-heating processes in industry.
TL;DR: In this paper, a straightforward approach to the utilization of digital computers in design is described and the choice of a performance index is discussed as well as the search procedure to be used in seeking the component values which minimize this index.
Abstract: A straightforward approach to the utilization of digital computers in design is described. The choice of a performance index is discussed as well as the search procedure to be used in seeking the component values which minimize this index. A realistic example of a pressure transducer is presented. The computer is used to choose compensating capacitors for the associated bridge circuitry with the objective of obtaining a linear (voltage versus pressure), temperature-independent response. The results are excellent both in terms of good design and reduction of design effort.