why we are called the 4-20ma transducer,not 0-20 ma transducer??

why we are called the 4-20ma transducer,not 0-20 ma
transducer??

Question Posted / arjun

3 Answers
5666 Views
I also Faced
E-Mail Answers

Answers were Sorted based on User's Feedback

why we are called the 4-20ma transducer,not 0-20 ma transducer??..

Answer / praveen kumar gupta

4mA is the minimum operating current of controling device

Is This Answer Correct ?

2 Yes

0 No

why we are called the 4-20ma transducer,not 0-20 ma transducer??..

Answer / vaseekaran

Let us keep the value as 0 to 20 mA,
The valve we measure in the output will be zero if the meter is in idle state and also it will show the same zero even the instrument is in fail condition.so we cannot get the exact and get confused if there is a problem in instrument while cross checking.this is the reason we are using 4 to 20mA.if the instrument fail then we can get only zero and if the instrument is idle we will get 4mA.so we can easily differentiate it.

Is This Answer Correct ?

2 Yes

0 No

why we are called the 4-20ma transducer,not 0-20 ma transducer??..

Answer / raja

There is a long tradition dating from the early pneumatic
instruments for a control range from 25% to 100%. If you
want to know why, look at the pressure vs travel curve for a
flapper-nozzle. The early electronic instruments used the
same force-balance approach (many with a 10-50 mA range -
easier to get a higher force with the higher current) which
was eventually translated over into the pure electronic format.

Is This Answer Correct ?

0 Yes

0 No

Post New Answer

More Electrical Engineering Interview Questions

I am working as maintenance engg. in electrical but i want to do carrier in electrical drawing.Tell me about that.

2 Answers

why rating of generator is kva but motor is kw ?

4 Answers

what is the difference b/w absolute encoder and incremental encoder?

0 Answers

What is the suitable transmission voltage?

0 Answers

what is the basic difference between synchronous motor,synchronous generator and induction motor

7 Answers NHPC, NTPC, Sail,

How you calculating the 30 Hp 3 phase AC motor of power what size of cable is used for this motor?

0 Answers Dhanam Enterprises,

better choice of area of interest to post in our resume?

2 Answers Cognizant,

what is the difference between neutral and earth

11 Answers

i have faced a problem in ro plant grunfos make bm30type pump it is 22kw pump. We start this pump using siemens 3rw 4423-ibc44, 30kw softstarter but this soft starter will frequently failier so we planed to change dol starter. So pls tell anybudy its possible or not.

0 Answers

what is the earth resistance ?

5 Answers Bhel, Cummins,

What is an Isolation Xformer? What is the use of it?

2 Answers

how can u do the earthing of an aeroplane?

5 Answers

For more Electrical Engineering Interview Questions Click Here