Answer / carl_ellis

What is the purpose of valve positioner. Explain 4 uses.

1) Use supply air pressure to ensure the correct valve
position through feedback control to overcome stiction or
forces on the valve plug.

2) Characterized the non-linear valve movement with respect
to the input signal, for instance, equal percentage or quick
opening

3) Provide position feedback to the control system via
conditioned process signal (4-20ma)

4) Provide adequate seat loading force to ensure tight
shut-off.

Carl Ellis
Measure First

Answer / as

Point No#2 The characterstics of valve for example
liner/equal percentage are defined by valve plug,cage shape
and not by valve positioner.

what is the difference between venturi and orifice meters?

9 Answers   Medha Servo Drives,

---

What is ptw and write 3 types of ptw?

5 Answers   Emco,

---

how to use one 4-20mA signal for two indicater or controller & give necessary precaution.

2 Answers  

---

why magnetic flow meter is not used in thermel power plant operation

2 Answers   JK Paper,

---

How INtools is useful for routine Instrument maintenance?

0 Answers  

---

Watt is Wrms define rms?

2 Answers  

---

the output of the common trasmitter protocol in qatar gas are the following

0 Answers  

---

i am confusing about differential pressure transmitter as i seen so many DPTs in different ranges how can we calculate level and flow with mmh20 plz tel me

1 Answers  

---

what is the working principle of dis-placer type level transmitter

1 Answers   Sendan,

---

why the derivative in PID is always set to zero?

3 Answers  

---

Can anyone provide me the details of GAIL test paper?What is the format and what type of questions will be there? my id-princegnb@gmail.com

1 Answers   GAIL,

---

need instrumentation job completed 1 year trainee ship in mnc pesticide company. now in search of job

0 Answers  

---