why we use 4-20 mA for calibration of the instruments.why
we cant use 0-20 mA?
- 5 Answers
- 9382 Views
- I also Faced
- E-Mail Answers
Answer Posted / vikash tiwari
4-20ma is a linear system.
Live zero system used in loop so 4-20ma use.
Various instrument use in a loop,when one instrument is faulty so not required to check all loop instrument in live zero system.
| Is This Answer Correct ? | 0 Yes | 0 No |
Post New Answer View All Answers
A PLC is programmed to drive three motors A, B and C as follows : After running motor A for an hour, motor B should get ON and motor A should get OFF. And after running motor B for an hour, motor C should get ON and motor B should get OFF. And after running motor C for an hour, motor A should get ON and motor C should get OFF. (That is, a cyclic repetition with time period one hour) Now, the second condition is: If any motor gone faulty and is tripped, the consecutive motor should get ON and the faulty (tripped) motor should be eliminated from cyclic repetition. The remaining two motors should bear the cyclic repetition of one hour each. (For healthy motor take logic as high and for tripped motor take logic as low) Now, the third condition is: When motor A load(Amps) exceeds 60% of its rated load, motor B should get ON in parallel to motor A. And when both motors A & B are running in parallel, and if their load exceeds 60% of their rated load, motor C should also start in parallel to A & B. [Here the cyclic repetition is eliminated, until their loads become normal(40%)] [Take logic high(1) for load at 60% and logic low(0) for load at 40%] Now draw a flow chart or a ladder diagram to fulfill the above condition.
I installed the smartplant instrument v8, but can not be opened, that always said: "INTools 2007 hardlock no found". So Could you help me how to do for that?
Why do we have earthing cable in branch cable and shield in the same cable?
hi my name is rakesh patel i just complited my be in instrumentation & control now i am going to working as a validation engineer in a poject department so what is a scope in a future as a validation engginer ? what line is good for me can any bady give me complete solution please? your regard rakesh patel
all questions related to instrument technician in any offshore oil and gas company.
In turbine what does term CDP, NH, HSSOC means.
hye SAM acn u send your e mail id, so that i can solve my query through e mail?
what different types of problems do occur while doing instrumentation commisioning and how to solve them? please explain in detail
while i check zero check for dp flow transmitter some fluctuating came (0 to 458 kg/h) what is the reason?
what diffrence b/w plc s7200,300,400
where i can get training in INTOOLS and PDMS in Delhi-NCR OR north part of India. please reply with ur ans. at arunsamkaria@ymail.com
how to convert cubic metre per hour to newton cubic metre per hour
in sulfur process what is material of impulse line we use to connect with transmitter ? and does teflon affected by sulfur?
How we can check the 2 wire proxy switch? & how it is connected to DI MODULE OF PLC?
Any body have know try work calculation ???
