Relays in Ladder Logic Tutorials
Electromechanical relays may be connected together to perform logic and control functions, acting as logic elements much like digital gates (AND, OR, etc.). A very common form of schematic diagram showing the…
Relay Principle & its Types
A relay is an electrically operated switch. Many relays use an electromagnet to mechanically operate a switch, but other operating principles are also used, such as solid-state relays. Relays are…
Differential Pressure Sensor for Filtration Monitoring
Differential pressure measurement is the difference in pressure between two points in a system. For filtration applications, the upstream side is positioned before the filter , whereas the downstream side…
Contact and Non-Contact Level Sensors
A good way to reduce the number of level measurement options is to categorize them into two broad categories: contact and non-contact. Then you can filter choices by the type…
Measure Flow rate using Level Sensors
Level sensors are capable of measuring more than just level. Flow rate measurement in an open channel can be accomplished using weirs and flumes.
Radiometric level measurement Working Principle
The radiometric level measurements work non-contacting and non-intrusive. As the components are mounted on the outer wall, they do not come into contact with the measured material and are therefore…
4-20mA Graphical Calculations
An illustration sometimes find helpful in understanding analog signal ranges is to consider the signal range as a length expressed on a number line. 4-20mA Graphical Calculations For example, the common…
Field Instruments Scaling and Unit Conversions
The Instrumentation and Controls is all about managing information. Today, process information must be prepackaged, timely, and accurate, so we in the controls profession must be adept at managing information, from…
Basic Process Control System
Consider a typical process control system. For a particular example let us look at an open tank, which supplies a process, say, a pump, at its output. The tank will require a…
ON-OFF Controller Principle
On-Off control is the simplest form of feedback control. An on-off controller simply drives the manipulated variable from fully closed to fully open depending on the position of the controlled…
