Answer / ajith294

Fire and gas system usually as part of a saftey system. the
percentage of Lower Explotion limit shall be dectected by
GAS detector and gives the alarm ,normally 20% is High and
40% is High High alarm.

catalytic bead sensor, semiconductor sensor, infrared point
sensor and ultrasonic sensor are using to detect the gases.

there was no establised standared to difine zero air for
calibration. some procedure says pure nitrogen and some
uses sytetic air. But much more realisitc and practical
using ambient air for zero calibration , when area is
considered to be clean.

for span calibration using 2.5 %Methene (CH4) and balance
nitrogen mixer. 2.5 %Methene (CH4)is equal to the 50 % of
LEL.

Answer / mohamed yousuf

fire and gas system is nothing but to detect the toxic,
flamable and combustible gases in the plant and also for
giving the awarness of the hazardous through beacons and
loudspeakers.

What is upsampling and downsampling?

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Explain the mechanism behind the turbine meter.

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what is the difference between transmitter and smart transmitter ?

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Pls can anybody tell me how much memory plc's has?in byte or in Kb

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why does a transmitter o/o signal starts from 3-15psi or 4- 20mA?

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A motor is taking 15 Amps at no load and 60 Amps at full load. and a valve has to open 10% at full load and 80% at no load. How to draw ladder logic.(PLC).

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defination of plc

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What is the procedure of DP switch calibration 

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in my company organisation in plan to take new PLC system for replacing old relay system , for that what I/P needsd to submit to the system house of PLC supplier?

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