Tag: instrumentation and control
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What are Control and Instrumentation Cables?
While power cables are what we can refer to the “arteries” of industry, control and instrumentation cables are its “nerves” and are used for the control of equipment and data collection. They range from switch-core cables utilized in the wiring … Read more
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How Synchros are used as Position Transducers
Let’s consider the transformer in Figure 1.0 whose secondary winding can be rotated with the respect to the primary winding. Figure 1.0 Synchro torque transmitter At an angle ϴ, the output voltage will be given by: Vo = KV… Read more
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Actuators as Automation Components
An actuator is normally controlled by the controller. The actuator, in turn, changes the output of an automated process. The actuator in an automated process may in actual fact be several actuators, each of which provides an output that … 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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Analog vs. Digital Controllers
Analog signals pass continuously through a full range of values for example a measuring device converts the process variable (PV), say temperature, into a signal corresponding to this temperature. Each temperature value corresponds to a value of the electrical signal. … 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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Steam-heated Reboiler Control System
When steam-heated reboilers are used in distillation columns and the heating medium is steam, a flow control loop for the steam will typically be incorporated. The control valve can then be placed either in the steam or condensate line. Steam … Read more
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Furnace Control System for a Rapidly Changing Demand
Let’s consider the figure below: Figure 1.0 Typical single-fuel cross-limited combustion control system In the system above, the output of temperature controller TC represents the process demand, and this signal is applied as one of the inputs, each to a … Read more
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Industrial Process Temperature Control System
Let’s consider the industrial process control system shown below: Figure 1.1 Industrial Process Temperature Control System The requirement is to control the temperature ϴ in the tank. The voltage r, obtained from a potentiometer, is calibrated in terms of the … Read more