Interested to Buy Any Domain ? << Click Here >> for more details...
Answer Posted / abdus sattar mollah
initially,0-20ma of current is used as an transmitting
standard unless a objection was met.It was that:0 ma of
current used to indicate no signal/minimum signal from a
signal conditioner but if there is a faulty condition(such
as loop break),then also it will be show 0 ma of
current.Operator may think that there is no signal but
actually a fault has occured.So he cant distinguish between
them unless the plant is damaged.This is called TRUE ZERO.
So,after a reserach a new standard was proposed i.e 4-20 ma
of current.There was minimum interference in this
range,good quality transmittance,low power consumptions.So
this satndard is used.
| Is This Answer Correct ? | 37 Yes | 1 No |
Post New Answer View All Answers
What pressure results for a flow transmitter of range 0- 180t/h in the dcs and 0-301mbar in the field using square root extraction. Kindly also suggest formulae for the percentages 0,25,50,75,100?
1.what is the effect of vapour presuure in orifice plate flow measurement 2.which is more effective 2 pressure sensors or one single differential pressure sensor in orifice plate measurement 3.how to design a v/i converter and i/v converter 4.how many type of thermocouple are there 5.how many leads are there in thermocouple measurement 6.how pressure sensors are connected in level measurement in differential pressure method 7.what is the output of capacitive pressure sensor (ac or dc),how its o/p is signal charactarized 8.what is the physical meaning of discharge coeeficient,why it is calculated,orifice plate what is its value,why it is less than 1,Q at upstream is equal to or not equal to Q at downstream of orifice plate why?what is vena contracta in orifice plate 9.why rotameter is called variable area flowmeter,it can measure flow even if area is not varying,why it is made tapered 10.design a 10 bit counter ,which counter you will prefer 11.how to remove self heating error in RTD 12.which is more sensitive pt100 or pt50 13.why thermocouple are connected in parallel 14.what is lead contact error in RTD,how to avoid 15.what is P,PI,PID,PD controller,why there is no ID controller 16.what is override,split range,sequential,ratio,feedforward,cascade controller 17.why we moved from SR to JK and then JK to master slave JK flipflop,give correct reason 18.how to measure level of a closed container which contains vapour and liquid,remember no vapour gas should be leaked,so ultrasonic and capacitive is not an option,design another method 19.how to design horse race counter including sensors and signal conditioning element 20.what is bevelling
why use 50% lel methane gas concentration for gas detector calibration instead of 60% lel gas concentration whereas the hi alarm set at 60% lel.
pls suggest suitable MOC of diaphragm for pressure measurement of UREA grade solution service fluid.
What are continuances of connecting earthing and shield of branch cables (instrument to Junction box), at the same earthing pot provided on JB? Is it ok, or may produce some problem?
How does temperature bath work? How does coil gets heated only by applying some current?
HOW TO SOLVE PROBLEM WITH ENRAF LEVEL TRANSMITTER 854 ATG THAT PASSWARD DO NOT Exist INTO TRANSMITTER TO ADJUST LEVEL WITH PORTABLE PET 847, WRITTEN WRONG PASSWORD , I AM SURE THAT DEFAULT PASSWARD (W2=ENRAF2) IS THIS TRANSMITTER NEED TO REPLACE SOFTWARE AND HOW?
Why MUX JB's are using only Temperature Element in Fundation field bus?
what is 24vdc live and dry supply
How to Calibrate Ultrasonic flow Transmitter in Field
typical loop drawing of a simple feedback control comprising of one transmitter and one control
describe flow nozzel principle?
What is the use of temperature compensation?
How does work A temperature valve or fv control valve in process plz brief me
What is the use of gauge?
