Tag: Industrial control
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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…
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Basic Elements of a Digital Controller for a Steam-Turbine Driven Generator
The block diagram below illustrates the basic elements of a minicomputer system for speed and voltage control as well as data acquisition of a steam-turbine driven generator unit. Typical output variables of the generator are speed, rotor angle, terminal voltage, field (excitation) current, armature current, and real & reactive power. A number of output variables…
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The Role of IO-Link (Single Drop Communication Technology) in Industrial Networking
The increasing application of microcontrollers in low cost sensors and actuators has provided opportunities for adding diagnosis and configuration data to support increasing function requirements. The chief reason for the development of a new technology called IO-Link has been the need for these low-cost sensors and actuators to exchange the diagnosis and configuration data with…
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Features of Popular Fieldbuses used in Industrial Networking
The commonly used fieldbuses are: Ethernet TCP/IP Modbus DeviceNet ControlNet Modbus TCP PROFIBUS-DP AS-I The Table below outlines the key features of popular Fieldbuses that are commonly used in Industrial Networking: Related articles: What is Fieldbus in Industrial Communication Networks? Typical Technical Aspects of Foundation Fieldbus Features of HART Communication Protocol Basic Features of Foundation…
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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 of inputs (both analog and digital) and control a small number of outputs or the…
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Types and Operations of Wired Ethernet Networks
Ethernet plays an important role as a communication platform for automation systems. The Key strength of Ethernet is in its ability to run many protocols simultaneously on the same network. Ethernet enables flexibility, scalability and performance of industrial networks in a way not seen before in automated systems. Principle of Operation of Ethernet Network Ethernet…
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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…