Conductivity Measurement
The electrical conductivity of liquids is an important analytical measurement in many industrial processes. This measurement is one of the more non-specific types of analytical technologies, because it does not…
Accelerometer Vibration Probe Principle
In simple language we say that vibration is a movement or mechanical oscillation about an equilibrium position of a machine or component. Vibration is a by-product of an otherwise useful…
Determining the Design Purpose of Override Controls
Override control strategies are a source of much confusion for people who first learning the concept. Perhaps the most fundamental question people find difficult to answer when faced with an…
How to Analyze a Cascade Control Loop?
Let us discuss a steam-heated reactor control system with a cascade strategy, where the temperature controller drives a setpoint signal to a “slave” steam flow controller: Cascade Control Loop In…
How to Analyze PID Controller Actions
The direction of action for a loop controller – either direct or reverse – at first seems like a very simple concept. It certainly is fundamental to the comprehension of…
Override Control Functions
An “override” control strategy involves a selection between two or more controller output signals, where only one controller at a time gets the opportunity to exert control over a process.…
Selector Control Functions
In the broadest sense, a “selector” control strategy is where one signal is selected from multiple signals in a system to perform a measurement control function. I will use the…
Limit Controls : High Limit & Low Limit Functions
A common application for select and limit functions is in cascade control strategies, where the output of one controller becomes the setpoint for another. It is entirely possible for the…
Limit, Selector, and Override controls
Another category of control strategies involves the use of signal relays or function blocks with the ability to switch between different signal values, or re-direct signals to new pathways. Such…
What Temperature are Celsius and Fahrenheit Value Same ?
Simple Conversions of Celsius and Fahrenheit Temperature Scales 1. Standard Conversion °F to °C : Deduct 32, then multiply by 5, then divide by 9 °C to °F : Multiply by…
