Tag: instrumentation and control
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Electric Solenoid Actuator – Features & Operation
A typical electric solenoid actuator consists of a coil, armature, spring, and stem. This is illustrated in the figure below: The coil is connected to an external current supply. The spring rests on the armature to force it downward. The armature moves vertically inside the coil and transmits its motion through the stem to the…
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Pressure Control Valve Operation
A pressure control valve is a spring-loaded valve that is capable of maintaining a constant pressure in a system regardless of the flow rate. This is important, since most pumps e.g. gear pumps are constant-displacement types – a constant volume of fluid is pumped for each revolution of the pump shaft. If the pump were…
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Basic Steps to Consider in Designing a Control System
Typically a control system should be designed to work together with an already existing process. The control design problem can be stated at local, supervisory or even plant-wide level. If we consider the local level, the typical steps in designing the control are: Most of these activities should be performed iteratively. For example, if the…
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Fuzzy Controller and its Industrial Applications
Fuzzy logic is a human model, potentially applicable to a wide range of processes and tasks that require human instinct and experience. In computer, truth-values are either 1 or 0, which corresponds to true/false duality. In fuzzy logic, truth is the matter of degree, hence truth-values ranges between 1 and 0 in a continuous manner.…
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Data Acquisition and Telemetering in Power Systems
To be able to manage and control a power system, the network engineer requires reliable and current information about the state of the network. He obtains this information from power flows, bus voltages, frequency and load levels along with the position of circuit breakers and isolators, the source of these data being in the power…
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Supervisory Control and Data Acquisition in Power Systems
The term supervisory control and data acquisition (SCADA) refers to the network of computer processors that provide control and monitoring of remote electrical or mechanical operation e.g. management of power distribution grid or the control of mechanical processes in a manufacturing plant. Typical the old SCADA systems would encompass computers and network links that manage…
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The Principle of Operation of Optical Encoders
An encoder is a device that provides a digital output as a result of an angular or linear displacement. The position encoders can be grouped into two categories: Incremental Encoders Let’s consider the basic form of an incremental encoder for the measurement of angular displacement of shaft shown below: The incremental encoder shown above consists…
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Features of Analog Signal Transmission
Analog voltage or current signals are hardwired between the transmitter and the receiver. These analog signals can be relatively be slow to settle compared to digital signals, due time constant of the lead capacitance, inductance and resistance. Analog signals can lose accuracy if the signal lines are long with high resistance. These signals can be…
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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 pressure transmitter with a typical functional diagram illustrated below: The process pressure is transmitted through the…
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Basic Features of Controller Area Network (CAN)
Controller Area Network (CAN) is a serial communication protocol developed primarily for applications in the automotive industry. It is also capable of offering good performance in other time-critical industrial applications. The CAN protocol is optimized for short messages and uses a carrier sense multiple access (CSMA)/Arbitration message priority (AMP) medium access control technique. Therefore CAN…