why 4-20 mA in covection system?

Answer Posted / ranganadh

Long distance communication mA signal is preferable than
mV, V signals to avoid noise. It cann't be predictable with
0 mA, whether the loop was broken or the signal itself. So
to avoid loop break problems we consider 4mA as the lowest
signal. Moreover, it is recommended to put a 250 ohms
resistor at the input terminals of the instrument to get
1VDC for 4mA and 5 VDC for the 20mA and further these
signals will be amplified by instrumentation amplifier in
the instrument circuit.

Is This Answer Correct ?    8 Yes 2 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

WHY THE DEGREE OF VALVE PLUG AND VALVE SEAT IS SLIGTLY DIFFERENT I CONTROL VALVE TRIM DESIGN

1557


How to Calibrate Flow Switch in field

774


State bernoulli’s application.

679


pls provide me syllabus and old question paper of instrumentation engineering for GET(JSPL)

1857


What is 1:1 redundancy ?

1890






Sir , i have completed my M.Sc In Instrumentation and presently working in Maintenance department 3 yrs Exp , is there is any possible for work in offshore ..

1408


What inherent design and operating principles are included in a modern control system to use predictive maintenance practices to increase overall system reliability?

1612


what is different between 2,3&4 wire rtd and how much maximum distance using plc to field.

2292


In dcs panel we are using diff type of modules ?what is module ? what is the use of modules ?diff type of module?

1500


Which type of pressure can be measured by these elements?

639


How to Calibrate Ultrasonic flow Transmitter in Field

805


in which principle pressure tx,level tx ,flow tx,temp tx ,control valve works?

2702


what is vibration a part of proceess variable? if vibration is a part variables then how we minimize the actual vibration on machine on load,? vision of instrumentation contrl plz ans me IPGDL interview question

1523


What is surge and how is it prevented, what is the purpose of bypass valve across AS valve.

1484


hi,i am doing 3 year in electronic and instrumentation engineering. what type of aptitude questions will be asked in a core industries and how can i improve my skills in instrumentation?

1661