When the disturbance is measurable, feedforward control is an effective means for cancelling the effects of disturbance on the system output. This is advantageous, since in a simple feedback system, the corrective action starts after the effect of disturbance is reflected at the output. On...
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June 19, 2016 admin
Control System, Instrumentation
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Most people have likely had the experience of adjusting water temperature as they took a shower with dual valves: one valve controlling the flow of hot water and another valve controlling the flow of cold water. In order to adjust water temperature, the proportion of one valve opening...
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February 20, 2016 admin
Control System, Instrumentation
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In a manually-controlled process, a human operator directly actuates some form of final control element (usually a valve) to influence a process variable. Simple automatic (“regulatory”) control relieves human operators of the need to continually adjust final control elements by hand, replacing this task with the occasional adjustment...
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February 20, 2016 admin
Control System, Instrumentation
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Ziegler-Nichols open-loop tuning procedure :- The first process tuned in simulation was a “generic” process, unspecific in its nature or application. Performing an open-loop test (two 10% output step-changes made in manual mode, both increasing) on this process resulted in the following behavior: From the trend, we...
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January 27, 2016 admin
Control System, Instrumentation
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Once while working as an instrument technician in a large manufacturing facility, a mechanic asked me what it was that I did. I began to explain my job, which was essentially to calibrate, maintain, troubleshoot, document, and modify (as needed) all automatic control systems in the facility....
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January 25, 2016 admin
Control System, Instrumentation
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First of all we will see a simple close loop control system. Below figure is simple close loop control system. ...
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December 29, 2015 admin
Control System, Instrumentation
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If liquid flow-control valve is opened in a step-change fashion, flow through the pipe tends to selfstabilize at a new rate very quickly. The following illustration shows a typical liquid flow control installation, with a process trend showing the flow response following a manual step-change in valve position:...
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December 16, 2015 admin
Control System, Instrumentation
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