Tag: Industrial 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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Key Factors to Consider in Selection of Valves
Valves are the final element in a control loop, and are critical in providing the correct flow. The valve, usually operates in very harsh conditions, and is one of the most costly elements in the process control system. Their selection and correct installation require both knowledge and experience. Understanding system requirements and manufacturers specifications is…
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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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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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Transfer Functions and Block Diagrams of Control Systems
Transfer Functions A transfer function is a mathematical formulation that relates the output variable of a device to the input variable. For linear devices, the transfer function is independent of the input quantity and solely dependent on the parameters of the device together with any operations of time, such as differentiation and integration that it…
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A Digitally Controlled Drill Press
The diagram below shows a digital control system for a drill press that includes: the input, digital processor, drill-positioning mechanisms, and sampled-data position control system. The process is controlled as follows: The processor receives the input data and determines the sequence of operations while storing both the sequence and the hole positions in the memory.…
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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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Advantages of Industrial Control Networks
Industrial networks have evolved to become an integral part of manufacturing replacing the point-to-point communication at all levels. At lower levels in the plant/factory setup, networks provide higher reliability, visibility and diagnosability and enable capabilities such as distributed control, diagnostics, safety and device interoperability. At higher levels networks can leverage internet services to enable factory-wide…