Answer / sam

Please let us know where you have seen this in a instrument
in the field. The normal standard signal is 4 to 20mA.

Answer / pannu

actually we use 4-20mA:-
1. it is a current signal so it does not have a signal drop
as in case of voltage there is a voltage drop depending upon
the wire resistance.
1. if the output of the instrument is 0% it gives out put as
4mA for 100% it gives 20mA.if line breaks no signal is
there we receive 0mA so that we can blow an alarm for no
signal.

Answer / george mathews

The answer in my knowledge is that if we use a 0 - 20 ma ,
in instrument then we cant distinguish if it is off/ close
stage or the wiring to the instrument is cut off some where
in the connection . Bcos in both the case we will get an
input as 0 ma. But when we us 4 -20 ma here we can say when
the instrument is close and when its wiring is cut off bcos
only then we can get 0ma and 4ma on different condition.

Answer / sreenivasulu

because of getting the accurate results we using 0-20ma in
instrumentation instead of voltage

What is the differerence between hysterisis and linearity.

0 Answers   CCIE,

---

What is the principle of capacitance type level transmitter?

0 Answers  

---

hi i want sov loop cheak from consol to field the operater given status to sov still no change, but MR room to sov ok so whats a problem and alreasy cheak all conection ok ?

2 Answers  

---

what different types of problems do occur while doing instrumentation commisioning and how to solve them? please explain in detail

0 Answers   Process Control Technologies,

---

Explain types of valves?

0 Answers  

---

in a power plant which system are compensated?

2 Answers  

---

How can I read the electrical drawing easily?

2 Answers   Plot Enterprise,

---

In Safe Guarding test what means by "Failed to Danger" ?

0 Answers   Optimal,

---

What is the basic principle of vibration measurement by BENTLY NEVADA vibration measurement system? and Why it gives the -ve voltage output?

14 Answers   Ensol, GNFC, Reliance, Siemens,

---

plz you help about Que paper of mahagenco previous your,any model paper relad to it{maharastra power genration}

0 Answers   MahaGenco,

---

How you calibrate absolute pressure with the calibration range of 0 to 1000 0C Absolute. Please explain the procedure for calibration.

0 Answers   Petro Rabigh,

---

what will be the pressure in tank which has the total level of 2 meters and is filled 1.2 meters ?

4 Answers   Engro,

---