Golgappa.net | Golgappa.org | BagIndia.net | BodyIndia.Com | CabIndia.net | CarsBikes.net | CarsBikes.org | CashIndia.net | ConsumerIndia.net | CookingIndia.net | DataIndia.net | DealIndia.net | EmailIndia.net | FirstTablet.com | FirstTourist.com | ForsaleIndia.net | IndiaBody.Com | IndiaCab.net | IndiaCash.net | IndiaModel.net | KidForum.net | OfficeIndia.net | PaysIndia.com | RestaurantIndia.net | RestaurantsIndia.net | SaleForum.net | SellForum.net | SoldIndia.com | StarIndia.net | TomatoCab.com | TomatoCabs.com | TownIndia.com
Interested to Buy Any Domain ? << Click Here >> for more details...

why do we use 4to20mA not a 0to20mA?

Answer Posted / simon marshall

The 4-20mA loop can be used with active sensors. The
minimum current of 4 mA powers the sensor. (The sensor then
must act as a variable current sink through its supply
terminals varying the current it draws in proportion to the
quantity it is sensing such as the millivolts or so from a
thermocouple, for a 4-20mA temperature gauge.) I do not
know how the powering current of 4mA was arrived at. The
specifications allow a range of maximum voltages for the
loop to operate on and the sensor power can then be
satisfied in different designs by altering the minimum
voltgage drop on the device. The item powering the loop
then must also be designed to measure the current drawn in
the loop but read out on a display with the transfer
funtion zero to full scale deflection = 4mA to 20mA

Is This Answer Correct ?    0 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

I am selected for interview jr executive(electronics)in AAI.i have the interview on 13th october2010.please anyone send the requirements and share the interview details who had completed.if u have any details plz send to srikkanth.283@gmail.com r @09491955876....i'm in tense.....

2011


What is the work of BOIA, TRx, BB2F, Duplexer, Combiner, Multi-coupler, RRI.

3352


What are the active wastes in nuclear submarrine and how they disposed or dump?

2105


please send me last year question for executive tranees in ntpc on my email ID rajthakur2091@gmail.com

2144


What does the voltmeter in ac mode show?

977


what would be main different environment in gsm and cdma core networking side?

1974


how can trace the fault in any PCB? what are the steps to find problem & to troubleshoot?

2019


Which is the fastest logic ?

1017


What is the function of freewheeling diodes in controlled rectifier?

1176


What is meant by voltage commutation?

1056


How to calculate the rectangle of conductor of different sizes?

1003


The processing speed of a microprocessor depends on _____?

1002


hi i am electronics & telecomm engg & appling 4 the AAI jr executive (electronics/ATC) written test. pls forward me the syllabus & old question papers.I will be very much thankful to you. pis inform to mpnisi@gmail.com

1954


What is the difference between led and lcd?

993


draw a ckt diagram i/p 230v & o/p 80v??????

2435