Industrial Control Systems - Instrumentation Tools

Override Control Functions

An “override” control strategy involves a selection between two or more controller output signals, where only one controller at a

In the broadest sense, a “selector” control strategy is where one signal is selected from multiple signals in a system

A common application for select and limit functions is in cascade control strategies, where the output of one controller becomes

Another category of control strategies involves the use of signal relays or function blocks with the ability to switch between

As we have discussed, feedforward control is a way to improve the stability of a feedback control system in the

Feedforward control works by directly modulating the manipulated variable in a control system according to changes sensed in the load(s).

Let us consider a liquid level control system on an open tank, where three different fluid ingredients (shown in the

“Feedforward” is a rather under-used control strategy capable of managing a great many types of process problems. It is based

A control strategy similar to ratio control is relation control. This is similar to ratio control in that a “wild”

Most people reading this article have likely had the experience of adjusting water temperature using two hand valves as they