Category: Mechatronics, Industrial Control & Instrumentation
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The Construction & Principle of Operation of Load Cells
A load cell converts a force (usually the gravitation force from an object being weighed) to a strain which can then be converted to an electrical signal by strain gauges. A load cell will typically have a local circuit as … Read more
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How Controllers are used in Industrial Automation Systems
In many process control systems, microprocessor based programmable logic controllers are used for decision making due to the sophistication of the system and the large number of process variables involved. The PLC can be configured to receive a small number … Read more
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Features & Configuration of a Smart Pressure Transmitter
Smart/Intelligent pressure transmitters are microprocessor-based, and they provide additional functional capabilities beyond their basic role of just sensing and representing a process variable; for example they provide computing, diagnostics, and networking capabilities . We shall consider a capacitive sensing … Read more
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The Conditioning of Thermocouple Sensor Voltages
Consider the circuit below: Figure 1(a) thermocouple signal amplifying circuit From the figure above, the sensing junction and reference junction are connected in series. When the junctions are at the same temperature the voltage output from the junctions is zero … Read more
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RTD 2, 3, 4 Wire Sensor Connections
The resistance temperature devices (RTD) can be connected directly to the controller peripheral amplifiers using 2-wire, 3-wire or 4-wire lead configuration. The wires in all these connections are in shielded cables. The RTD is usually driven from a constant current … Read more
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How Signal Processing Circuits are protected from high currents & voltages
Protection against high currents and voltages is a very important requirement for signal processing circuits. A high current can be protected against by the incorporation in the input line of a series resistor to limit the amount of current flowing … Read more
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Features of Stepper Motors & How they are applied in Industrial Control
A stepper motor is a permanent magnet or variable reluctance DC motor that has the following characteristics: It is able to rotate in both directionsIt can move in precise angular incrementsIt can sustain holding torque at zero speed… Read more
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How Servo Motors are used in Process Control
Servo motors are continuous motion mechanisms that use feedback signals to provide position and velocity control in a closed loop system. Servo motors can rotate to a given position be stopped and reversed. The angular position and speed can … Read more
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Methods of Protecting Instruments from Explosive Atmospheres
The protection method used in a specific hazardous location depends on the application, the technology available and the specific explosive atmosphere present. In this article, we discuss the following methods of protection: Encapsulation Explosion-proof and Flameproof Increased safety Intrinsic safety… Read more