Instrumentation Earthing
Earthing is the process of creating an alternative path for the flow of fault/excessive currents safely into the ground in the presence of minimal resistance or impedance. The primary purpose
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Category : Control Systems
Control Systems Theory
Process Control Loop Testing
A very useful technique for testing process control loop response is to subject it to a “step-change” in controller output. In other words, the process is perturbed (the highly technical
Identify Level Control Loop Tuning Problems
A level control loop is supposed to maintain a constant level of liquid at the bottom of the stripping tower where considerable amount of vibration exists, but it seems to have
Process Control High Level Alarm Fault Analysis
An operator reports a high level alarm (LAH-12) displayed at the control room for the last 13 hours of operation, in this sour water stripping tower unit (where sulfide-laden water
Compressor Emergency Shutdown Root Cause Analysis
The compressor emergency shutdown system (ESD) has tripped the natural gas compressor off-line three times in the past 24 hours. Each time the operator goes to reset the compressor interlock,
Liquid Flow Control Loop Controller Action
A liquid flow control loop consisting of a flow transmitter (FT) to sense liquid flow rate through the pipe and output an electronic signal corresponding to the flow. A flow
Readings Mismatch between Field & Control Room ? Why
Instrumentation maintenance engineer often hears about process value mismatch from field transmitter display reading and control room DCS/PLC reading. Generally we see the readings mismatch between field & DCS happens
Difference between DCS & PLC Systems
DCS stands for Distributed Control System and PLC stands for Programmable Logic Controller. Do you know the Difference between DCS and PLC Systems ? Difference between DCS & PLC Systems
BASICS OF TRIPS, INTERLOCKS, PERMISSIVES & SEQUENCES
This post provides information about basics of Trip, Interlock, Permissive and Sequences which are regularly used in instrumentation control systems like ESD, DCS, PLC etc. Trip: The term Trip refers to an action that
Boiler Three Element Controller Philosophy
A single element control system is one with just one control input, a two element control system is one with two control inputs, etc. A three-element boiler water level control