Answer / kinjalkumar chauhan

1) because output is linear in that region.
2) if communication wire brokeup then we come to know that.

Answer / carl_ellis

1) A current signal has the same current in all parts of the loop, unlike a voltage that drop voltage over distance, which provides reliability that a voltage signal does not.

2) A current signal is more resistant to noise pickup than a voltage signal is.

3) A live zero at 4mA allows for '2 wire operation', where the power for the loop uses the same two loop wires as the signal, a critically important feature for geographically dispersed industries like oil & gas, steel, paper and mining. 2 wire loop powered transmitters use about 3.5 or 3.6mA of current to operate the transmitter.

4) A live zero is a diagnostic detection of an open circuit

5) 4-20mA is a low enough current with limited energy that transmitters can be designed to operate intrinsically safe in hazardous areas with the appropriate barrier protection from faults in the safe area.

6) The DC current signal is suitable for superimposing a modulated FSK signal used by HART for digital communications that allow for configuration, troubleshooting, diagnostics or multivariable data transmission, all while retaining an analog primary variable

7) 4-20mA drives considerable sized loads at fairly low DC voltages, allowing for a relatively long distance signal path (1-2km depending on wire size). 20mA has a relatively low IR drop.

Close loop and open loop diagram for instrumentation

1 Answers   Petron ltd,

---

what is o2 analyzer and how it measured ,what is the role of this analyzer in cfbc boiler...

0 Answers   Mittal Steel,

---

how many pulses are required by a ac induction servo motor of 4 poles with 50 Hz frequency to rotate by 1 degree?

0 Answers   United Phosphorus,

---

EXPLAIN SOME IMP QUESTIONS AND ANSWERS ON TOPIC ELECTRONICS,INSTRUMENTATION.........

1 Answers   ONGC,

---

Any Transmitter Range (Span value) start from 2?

1 Answers   Exxon Mobil,

---

---

what sud u do if u dont get feedback from control valve?

1 Answers   Siemens,

---

can we use flow transmitter instead of level transmitter?

7 Answers  

---

what is modbus?and why use it?what benifit

2 Answers  

---

relation between level and differential pressure.

3 Answers  

---

i have one tank of 500mm height, which is in under vacuum of 735 mmHg, I want measure level of the same using DPT , SO WHAT WILL BE THE URV & LRV, DENSITY OF THE TANK FLUID IS 0.95. is there necessary to fill the LP side with fluid.

7 Answers  

---

a pressure transmitter with a range of 0 to 2500kpag has a specified accuracy of 0.5 % of span.It is to be calibrated using a comparison gauge to have an accuracy of 0.1% of span.The comparison gauge has a range of 0 to 3000kpag What is the accuracy ratio? is this ratio acceptable?

1 Answers  

---

What is the exact output of eddy current proximity probe? For vibration mesurment?

2 Answers  

---