Tag: process control
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Types of Load Cells and How Do They Work?
In the vast landscape of industrial measurement, load cells play a pivotal role in ensuring the accuracy and reliability of weight and force measurements. These sophisticated devices, integral to myriad applications across industries, convert mechanical force into measurable electrical outputs.… Read more
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Programmable Automation Controllers (PACs) – Features & Applications
What are Programmable Automation Controllers? Programmable automation controllers (PACs) are process controllers with an open configuration and possessing the enterprise integration power of a PC-based structure. In other words, PACs are industrial controllers that combine the functionality of a programmable … Read more
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Basic Features of Cascade Control
A cascade control system typically consists of a primary or master controller that generates a control function that serves as the setpoint for a secondary or slave controller. That controller in turn utilizes the actuator to apply its control function … Read more
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Combustion & Temperature Control for a Direct-Fired Process Heater
The figure below shows the control schemes applied to a direct-fired process heater. Fig: Combustion & temperature control on direct-fired process heater From the diagram above, the heat from the burning fuel is applied directly to the tubes carrying the … Read more
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How PLC Systems are Protected from Plant Voltages
Internally a PLC typically operates at 5 V dc. The external devices such as solenoids, limit switches, motor starters, etc. operate at voltages up to 110 V ac. The mixing of these voltages will cause irreparable damage to the PLC … Read more
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Key Requirements for Industrial Control Computers
A computer is often used as part of a control system. The input data is typically from the operator’s commands and signals from the plant (flows, pressure, temperatures, limit switches, etc.). The output data comes in form of … Read more
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Centralised vs. Decentralised Control Systems
Centralised control is usually carried out via computer software, having as inputs all the available sensors and producing signals for all the available actuators in the system. This control strategy is the most powerful, at least in theory, capable of … 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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Hierarchical Control Strategies for a Process Plant
In a process plant, we typically have a number of control goals that require different algorithms and types of information from the process; from the level closest to the process to the plant-wide control. All these activities ought to be … Read more
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Manipulating Devices & Actuators in Process Instrumentation
The function of the manipulating device is to influence the process variable. Its main purpose is to regulate a mass or energy flow. Mass flows can be either in gaseous or liquid state e.g. steam, natural gas, fuel oil, etc.… Read more