in instrumentation why we are using 4-20mA , why not
voltage ? if somebody design a instrument which works on
voltage then can we use that instrument?
Answer Posted / 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
| Is This Answer Correct ? | 0 Yes | 0 No |
Post New Answer View All Answers
Explain how thw analog to digital converter works with the circuit diagram
How do you identify between actual alarm and false alarm in a Temperature Transmitter in SCADA based Control System
what is function of switch, and how is it work, explain with difination
Derive capacitance to 4-20ma conversion formula / relation in capacitance type pressure sensor?
(1) In turbine, what does term CDP, NI, NH, HSSOC, means. (2) What is the purpose of LO overhead tank in turbines.(3) An equipment is certified for EEX, IA, IIC,T6, what do you under stand by this.(4) what is SURGE, and how it is prevented, what is the purpose of bypass valve across AS valve.(5) Give 2 application of quartz crystal used for process parameter measurement.(6) what is meant by cold float of compressor shaft. (7) state four different types of flow measurement. For gas flow measurement mmscfd is the common unit. Expand the unit and specify significance of word S in the unit.(8) what is meant by Gap voltage, in vibration measurement. Normally how much Gap voltage is set and state the reason.(9) what will the new flow factor if D/P transmitter is Re-Ranged from 25” wc to 50” wc.(10) what is the usage of QDV & Volume booster.
line up procedure for dp type flow transmitter?
What is zero elevation and zero suppression?
How does your previous experience relate to the job you are applying for ?
anybody having Qatar Petroleum questions for instrument Technician offshore ....please send me
what is commisioning procedure,2)what is is the main work in commisioning in the field tx to dcs, plz send me detail
why direct mounted pressure transmitters is always installed with DBB ( double bleed block) valve in process line or top of the tanks ?
how can be calibrate flow indication transmitter (rosemount) it shows excess milli amps nearly about 24 ma on full scale, but its scale was set on 20ma on full scale..???how can be simiulate..???
when the instrument tapping on pipe line is located below and transmitter is located above the tapping point for liquid service transmitter, what should we do, is there any additional drain valve is required??
what is the responsibility of an instrument commissioning supervisor
What is the purpose of bypass valve across AS valve.