Answer / samik

@17
Very nicely explained sir.

Answer / ashish namdev

YES

1. put air pressure at a certain value (according max air requirement for actuator full action )

2. then connect limit switch at several position (0-100 scale)

3. then make a logic for open & close control action with use limit switch feedback.

4. connect air inlet with solenoid or pilot valve.  

Ashish Namdev (Sr. Engg)
Jaypee Power Plant, 
Bina (MP)
  

Answer / ravi vaya

We can use control valve without positioner .
But control valve spring opareting range must be 3 to 15 psi

Answer / kamesh.g

No we can not control the control valve without positioner
eccept on-off type control valves ,Positioner main purpose
is boostup the air signal from I/P and put the position as
per your requirement ( Command)positioner link rod will
give the feedback to control valve air command air supply
so it can adjust the valve in correct position.

Answer / m.ra

Yes we can operate a control without a positioner in the
following condiotions.

1) Volume booster is not required.
2) Operation of control valve will be very sluggish.
3) Charecteristics of control valve cannot be changed.
4) If the valve is self regulation than also positioner is
not required.

Answer / ajith294

here more answers reagrading positioner

maximum of the answers are 'YES' especially Answer number
10,
then i have a doubt that how control a valve at 50% open,
with out a positioner.

if there is not a positioner, how we can control the valve
( control the pnumatic pressure is applied the
actuator)?????

if a valve it using fully open of fully close condtion
throgh Solenoid Valve ( bypass the air to actuator) is on
off valve.

Without a positioner we cannot control the valve through a
controller.

thanks

Answer / sandy

The name itself indicates the function of the positioner. A
control valve without positioner will act as a ON-OFF valve.

Answer / yogesh

On-off control valve can use without positioner. but globe
control valve can not use without positioner.

Answer / akg d gr8

yes, Positioner is used to show the position of the valve.

Control valve operates based on feed back from Transmitter
through PID Controller.

What is the difference bitween control net scaner and device net scaner

0 Answers   Binani,

what is the formula for changing Range of Transmitter from X mmwc to some Y mmwc with respect to DCS NCMH flow range from x NCMH to y NCMH?

1 Answers   HCL,

How a conductivity sensor & analyzer work at boiler, whats the principle & science is beyond this,How conductivity sensor sence & convert signal & move toward analyzer & analyzer show reading in percent? also what is temperature compensate option in conductivity analyzer

0 Answers  

wht is Zero Elevation and Zero Suppression?

12 Answers  

in the construction field why hook up s.s.tubing for transmitter using upto 6mtrs of closed loop, but y not open loop nomore restriction

5 Answers   Sabic,

what are the diff. in servo and regulatory control?

0 Answers  

How much should be the values and/or percentages of these given below factors for a good controller ? Steady state error Delay Rise Time Overshoot Peak Time Settling Time Damping Oscillations & vibrations thanks

1 Answers  

How to Calibrate variable Head flowmeter (Orifice), here we dont know High pressure and low pressure then how to apply pressure on HP and LP side ?

1 Answers   Nirma,

what is solenoid valve?

6 Answers   Hindustan Zinc,

Functions of electropneumatic valve positioner:

4 Answers  

whatis diference between zero pressure and obsolute pressure

1 Answers   ABB,

centrifugal compressor interlock? Tell me the parameter at which compressor will trip

0 Answers   Cairn,