Category: Mechatronics, Industrial Control & Instrumentation
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Passive vs. Active Sensors
Sensors are normally used to convert physical variables like pressure to signal variables. Sensors are also often termed to as transducers since they are devices that convert input energy of one form into output energy of another form. Sensors can … Read more
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The General Principle of using a Servo Motor for Position Control
Servo motors are typically employed in closed-loop position control; for example let us consider the following application, where the angular position of the output shaft is intended to follow the reference voltage (ϴref). Figure 1.0 Closed loop angular … Read more
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Designing a System to Measure & Display a Shaft Rotation Speed
We would like to design a system to measure and display the rotational speed of a shaft. To accomplish this, we shall use a number of integrated circuits (ICs) to create the desired functionality of this system. A simple technique … Read more
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What is a Microsyn Transducer?
This is a variable-reluctance transducer used to detect small motions, giving output signals as low as 0.01° of changes in angles. The figure below shows an example of Microsyn: In the Microsyn transducer above, the coils are connected in such … Read more
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Null vs. Deflection Type Instruments
Null Instrument The null technique is one of the operational modes for a measuring instrument. A null instrument employs the null method for measurement. In this technique, the instrument exerts an influence on the measured system so as to oppose … Read more
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Analog vs. Digital Sensors
Analog Sensors Analog sensors provide a signal that is continuous in both its magnitude and its temporal (time) or spatial (space) content. Most physical variables such as, current, pressure, temperature, displacement, acceleration, speed, light intensity and strain tend to be … Read more
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Variable Capacitance Sensors
Several mechanical input sensors, as well as some sensors which measure humidity or temperature, operate by the transduced quantity causing a change in capacitance, which in turn, is converted to an analog output voltage by an ac bridge circuit or … Read more
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DC Motor Power Op-amp Speed Controller
Let’s consider the functional diagram below: Figure 1 DC motor power op-amp speed controller functional diagram The D/A converter outputs a voltage directly related to the potentiometer position. However, the D/A converter’s output current is limited and not enough to … Read more
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Basic Features of Power Semiconductor Controlled Drives
Power electronics deals with the applications of solid state electronics for the control and conversion of electric power. The conversion systems require switching power semiconductor devices on and off. The key components of an electric drive controlled by a power … Read more
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How to calibrate a dc voltmeter
An instrument may be calibrated by comparing its reading with that of a more accurate instrument when both are measuring the same quantity. The more accurate instrument is used as a standard for comparison purposes. The figure below illustrates the … Read more