There is much to be said for neatness of assembly in electrical signal…
As discussed at the beginning of this chapter, instrumentation safety…
“Feedforward” is a rather under-used control strategy…
PID control can be a confusing concept to understand. Here, a brief…
Every programmable logic controller must have some means of receiving…
A simple control system drawn in block diagram form looks like this:…
A technological advance introduced in the late 1980’s was HART,…
Learning PLC programming is a very important skill. If your job…
Volumes could be written about poor diagnostic technique. The…
An exciting development in industrial instrumentation is the…
Modern analog-to-digital converters are phenomenally accurate,…
A 4 to 20 mA current signal represents some signal along a 0 to 100…
The advent of “smart” field instruments containing…
The reason why a pneumatic control valve’s stem position…
In the United States, the most common language used to program PLCs is…
Disturbances in the liquid tend to complicate liquid level…
Those familiar with industrial instrumentation will find much within…
The vast majority of PID controllers in service today are digital in…
The purpose of a control valve actuator is to provide the motive force…
In addition to directly performing logic functions, electromechanical…
Valve actuators provide force to move control valve trim. For precise…
Learning is not merely a process of information transfer. It is first…
A limit switch detects the physical motion of an object by direct…
The digital multimeter (DMM) is quite possibly the most useful tool in…
Level gauges are perhaps the simplest indicating instrument for liquid…
A different strategy for controlling the flow of fluid is to insert a…
A great many chemical composition measurements may be made indirectly…
Much has been written about the benefits of robust PID control.…
This section does not describe a particular type of flowmeter, but…
Perhaps the most basic and necessary protective relay function is…
A powerful mathematical concept useful for analyzing practically any…
Perhaps the most important rule to obey when using pneumatic…
As we have seen, feedforward control is a way to improve the stability…
Calculus has a reputation for being difficult to learn, and with good…
The following photograph shows a large air blower in a wastewater…
In this section I will show screenshots from a process loop simulation…
Two extremely important principles in electric circuits were codified…
Many traditional flowmeter technologies respond to the volumetric flow…
A Safety Instrumented Function, or SIF, is one or more components…
The two “process variables” we rely on most heavily in the…
