Answer / bnp

because there is voltage drop as per the length of conducting wire. but current has no drop

Answer / pradeep patil

Current 4-20 mA is prefered than voltage because:--
1)current signal can be carried to long distance without
drop in signal strength.
2)Less Electro Magnetic Interference effect in current
signal
3)no short crcuit spark happpens when signal cable
accidently short each other.
If your controller works on voltage (1-5 vdc) then 4-20 mA
can be easily converted in to voltage after connecting 250
ohm resistance accross signal cable as per ohms law.

Answer / himanshu

4-20 mamps is best choice because interference level is
minimum in current application where as in 0-10 V it is
comparatively high.Thus in using 4-20 mamps signal is
distortionless.

Answer / b0nz0

Most of the above answers are valid, but none have
mentioned security. If a current loop is broken then the
current will fall to 0.

Answer / yogi40

if we use voltage there there is noise interpretation
where as in current it wont happen
and current supports 2 wire connection,voltage doesnt
there will be drop in voltage when its feedback in current
such loss is very less

Answer / manuraj singh sengar

no, because voltage makes fluctuation & current remains
constant.

what is the analog input , analog output , digital output, digital input geven to the MSSV , CBD, IBD , START UP VENT , BOILER FEED PUMP , AOP, CEP , ETC

1 Answers   Bharat Biotech, TATA,

What is difference between loop and zone ?

5 Answers   Adgas, Bilt,

Explain about the leakage class of the control valves

0 Answers   CCIE,

How can we say that accuracy of measurement increases by using 3 or 4 wire RTD? because for example: If resistance of RTD element is say r ohms and Resistance of the cable from transmitter to RTD is R ohms And if 4 wire RTD is used, ____._____________________ R ohms | |_____._____________________ R ohms / \ / r ohms \ \ | |______.__________________ R Ohms | |_______._________________ R ohms Then the actual resistance measured will be: Total = r + R/2 + R/2 = r +R Ohms Note: r+R instead of r ohms. hence error

2 Answers  

we callculat main steam flow by D.P. but where is H.P. & L.P. IN Orfics?

3 Answers  

Describe all types and levels (4-20mA, 0-10V, mV, pulse, etc.)of analog and digital I/O used in process control application.

2 Answers   Jindal,

Displace type LT to be calibrated in workshop, wt. 40, dia- 60 mm, density- 0.8kg/cm3.

0 Answers   CCIE,

what is the difference b/w wet leg & dry leg level method

2 Answers  

What are the two states of a controller

3 Answers  

why I need valve guard and whats different between guard and positioner ??

0 Answers  

what is the imbustion control loop

0 Answers   Manali Sugars,

Please asked me How calculate DCS controller memory.

0 Answers   Yokogawa,