Areej – Instrumentation and Control Engineering

Difference between Data Highway and Data Highway plus

August 31, 2018 by Areej

The Data Highway and Data Highway plus systems are Local Area Networks (LANs). They connect programmable controllers, computers, and other devices so they can communicate and exchange data with one another. A cable system is the physical means of transmitting this data…

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Difference between Inverse Time Circuit Breakers and Instantaneous Trip Circuit Breakers

August 30, 2018 by Areej

Inverse Time Circuit Breakers Inverse time circuit breakers have both thermal and instantaneous trip features and are preset to trip at standardized levels. This is the most common type of circuit breaker used in the building trades for residential, commercial, and heavy…

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Difference between profibus and foundation field bus

August 30, 2018 by Areej

Profibus ProfiBus (PROcess FIeld BUS) is a widely accepted international networking standard, commonly found in process control and in large assembly and material handling machines. It supports single-cable wiring of multi-input sensor blocks, pneumatic valves, complex intelligent devices, smaller sub-networks (such as…

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Introduction to Industrial Ethernet

August 30, 2018 by Areej

Industrial Ethernet Early Ethernet systems (of the 10 Mbps variety) use the CSMA/CD access method. This gives a system that operates with little delay if lightly loaded, but becomes very slow if heavily loaded. Ethernet network interface cards are relatively cheap and…

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How to convert mA signal into % in instruments?(ie 4-20 mA=0 to100%)

August 29, 2018 by Areej

Example calculation: controller output to valve An electronic loop controller outputs a signal of 8.55 mA to a direct-responding control valve (where 4 mA is shut and 20 mA is wide open). How far open should the control valve be at this…

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Introduction to some important pneumatic components

August 29, 2018 by Areej

Main pneumatic components All main pneumatic components can be represented by simple pneumatic symbols. Each symbol shows only the function of the component it represents, but not its structure. Pneumatic symbols can be combined to form pneumatic diagrams. A pneumatic diagram describes…

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PRESSURE SPRING THERMOMETERS

August 28, 2018 by Areej

Introduction The construction and mechanical operation of all types of pressure spring thermometers are identical. The thermal system of pressure spring thermometer contains a metal bulb, capillary and receiving element. Metal bulb contains a thermometer fluid, a liquid or a gas or…

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Procedures to do before starting up and shutting down a differential pressure transmitter

August 28, 2018 by Areej

Installation: After installation and before start up of the differential pressure transmitter, be sure to perform the following checks and procedures. Preparation: (1) Check for liquid or gas leakage of the process connection by applying soapy water or similar. (2) Check of…

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Difference between filled impulse line and purged impulse line

August 27, 2018 by Areej

Filled impulse lines An alternate method for isolating a pressure-sensing instrument from direct contact with process fluid is to either fill or purge the impulse lines with a harmless fluid. Filling impulse tubes with a static fluid works when gravity is able to keep the fill…

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Different types of calibration

August 27, 2018 by Areej

Definition and Need for Calibration According to Webster’s Dictionary, calibrate means “to check, adjust, or standardize systematically the graduations of a quantitative measuring instrument.” As noted in Inter-Range Instrumentation Group (IRIG) 118-98 Volume I, “a telemetry system measurement begins with the sensing…

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