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The sentinel value is a form of in-band data that makes it possible to detect the end of the data when no out-of-band data (such as an explicit size indication) is provided. The value should be selected in such a way that it is guaranteed to be distinct from all legal data values since otherwise, the presence of such values would prematurely ...
A control loop is the fundamental building block of control systems in general and industrial control systems in particular. It consists of the process sensor, the controller function, and the final control element (FCE) which controls the process necessary to automatically adjust the value of a measured process variable (PV) to equal the value of a desired set-point (SP).
In these examples, if N < 1 then the body of loop may execute once (with I having value 1) or not at all, depending on the programming language. In many programming languages, only integers can be reliably used in a count-controlled loop. Floating-point numbers are represented imprecisely due to hardware constraints, so a loop such as
Control dependencies are dependencies introduced by the code or the programming algorithm itself. They control the order in which instructions occur within the execution of code. [4] One common example is an "if" statement. "if" statements create branches in a program.
Example of a single industrial control loop; showing continuously modulated control of process flow. A closed-loop controller or feedback controller is a control loop which incorporates feedback, in contrast to an open-loop controller or non-feedback controller. A closed-loop controller uses feedback to control states or outputs of a dynamical ...
Example of a single industrial control loop; showing continuously modulated control of process flow. A closed-loop controller or feedback controller is a control loop which incorporates feedback, in contrast to an open-loop controller or non-feedback controller. A closed-loop controller uses feedback to control states or outputs of a dynamical ...
An isolated distended loop of bowel is seen near the site of injured viscus or inflamed organ. This loop is called a "sentinel loop." It arises from the body's efforts to localize traumatic or inflammatory lesions. The local distention of that intestinal loop is due to local paralysis and accumulation of gas in the intestinal loop.
Many PID loops control a mechanical device (for example, a valve). Mechanical maintenance can be a major cost and wear leads to control degradation in the form of either stiction or backlash in the mechanical response to an input signal. The rate of mechanical wear is mainly a function of how often a device is activated to make a change.