Interested to Buy Any Domain ? << Click Here >> for more details...
Answer Posted / warren holden
Yes, a control valve can be used without a positioner.
Some of the previous responses contain correct information
about certain elements of what a positioner actually does
however they do not address the fundamental issue from a
control perspective.
The positioner on control valve is essentially a cascade
(inner) loop acting as a high gain proportional controller
within the external (outer or master) loop (Shinskey, G.F.
1988). The positioner will be beneficial if its response
time constant is faster than the master loop element(s)
i.e. in the case of a temperature control (master) loop the
control valve positioner dynamics will undoubtedly be
faster than the temperature measurement change dynamics
(this being a fundamental requirement of cascade control).
However, the control valve positioner is of no use, and
actually a hindrance, on fast acting master loops i.e. flow
control with fast change dynamics. Hence control valve
positioners are often not used on flow control loops where
the outer (master) loop flow measurement and associated
controller can handle the control valve positioning quite
well themselves.
| Is This Answer Correct ? | 1 Yes | 0 No |
Post New Answer View All Answers
HI friends.I am Surya a BTech in Electronics and Instrumentation Engineering.I am going to appear Relince Industries Ltd all India writen test very soon. so plz help me by sendind the probable questions about my subject.My mail ID is surya.barik@gmail.com.
sir, i preparing hpcl,ongc,barc,hal exams(instrumentation engg)pls send a placement papers
How digital input and digital output 's are working in dcs
Which type of pressure can be measured by primary elements?
can any one tell me when ongc placement test and its forms is available????/ pls tell me if u know
detail of mass flow meter pricipal
hi friends,im an instrumentation and contol engg student,can u hlp me of suggsting barc written question paper,my id is roysuvaranjan@gmail.com, cel no.9563591747
kindly sent some demo question and answer
How to calculate mmwc values into tonnes?
What is defferent betwen ESP &PCP PUMP .HOW IT IS WORK?
Hello to all....I am an Instrumentation Graduate and i am passed out in this year only.. I am unable to find the job in my core instrumentation.. so any boby tell me how to and where to search the job....please...and also tell me i there are any courses offered in the instrumentation stream so i can do it... you can send your suggestions to my mail-id i.e Ganesh20084u@gmail.com ... please..
what is interface level and how it is calibrate?
How addressable fire systems work? Pl. send details with architect.(Loop), also send details regarding Gas system. Pl. help me.Thanks
what is the criteria to decide conductor size of a cable ?
what is stroke check for field instument transmetter's & AOV's
