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
how to turbine speed measurement?
Why we are using DPT(Differential Pressure Transmitter) in separator instead of level trasmitter?
what are the documents(Construction point of view for a process plant) submitted by contactor initially entering in to new site for client?
How ejector(or)evactor air pump is working in thermal power plant?
What are different types of control valves?
Difference between 2-Valve Manifolds, 3-Valve Manifolds and 5-Valve Manifolds 3 with diagram
hi sir yhis is zahid ali i am preparing for the jspl at oct.4.please send me the recently updated sample paper.
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
how many types of spped sensors n vibration sensors?their basic principle n connection?
Hi Friends i need Electronics&Instrumentation Engg question papers for BARC written test by coming 20th May 2008 pls post ur use full info to kkumarei@gmail.com. Or for suggestions pls give one missed call to 9962122264
what is moisture probe? What are there types? What is there working principle and how they works? guys this is one of technical question I had ask in interview. If you know its answer please let me know. The interviewers were more interested in microwave moisture probe, so if you find its any link please just forward me on my mail id.avinash1200@gmail.com Thanks in advance.
what is function of sensor, and how is it work , explain with difination
What is critcal speed. what is resonant frequency. why we want to cross crtcal speed on higher RPM (early).
How will you test a transistor with a multimeter?
I have 0.75mm sq multicore cable (IS type) , can use instead of same type but 1.5 sq mm cable ? Note : The distance is around about 150 meter.
