In programming, a variable that keeps track of the number of iterations of a process. Its value is incremented or decremented with each iteration, and it is compared to a constant or other variable to ...

In science, a variable is something that can be changed, measured or controlled in an experiment. Scientists look at variables to understand how they affect things. A variable is any one of the things ...

This application note describes a closed loop, computer- controlled, variable attenuator for the control of output power from a tunable laser. It is based on the combination of a 1/2 wave-plate and a ...

The goal of controlling a system is to reach or retain stability. In control theory, stability is described with the Lyapunov stability criteria and mathematical models that set into relation the ...

In this article, as in industry, advanced process control (APC) refers primarily to multi-variable control. Multivariable control means adjusting multiple single-loop controllers in unison, to meet ...

The LMH6521 device contains two high performance, digitally controlled variable gain amplifiers (DVGA). Both channels of LMH6521 have an independent, digitally controlled attenuator followed by a high ...

Just over a decade ago, an article titled, "Advanced Control Strategies Move into the Field" (Control, October 2008), highlighted three evolving trends in the process control world that would "make ...