Answer Posted / kavi

Both are used to control a process. The on/off valves are
actuated by simple digital signal ( may contain voltage of
24 vdc/ac to 220vac) from an on-off controller or from a
controller whose output is of "on-off PID". In the first
one when the process exceeds a set value ( increase or
decrease) the digital output goes to valve to operate a
solenoid whose air supply opens or closes the valve ( a
full close or open condition). If the controller is having
an on-off PID the digital signal going to the valve is the
output of PID block of the controller which is in the form
of pulse width modulated one. In this also the valve will
have only two states like fullopen or full-close. In the
so called PID valve, the valve can have any postion of
opening basing on the analog signal received from the
controller. We can say that the valve opens or closes
proportional to the analog signal from the controller. In
this the controller tuning ( setting the values of P, I D )
has to be done by the process operator or the concern
instrument engineer/technician.

What are different types of valves?

1336

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What is 3 selection available when configure the burnout protection for controller

2705

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can anyone can let me know in Eurotron Micro cal 2+ calibrator in milli amps source mode we are not able to get 20 milli amps output it only produces 1.52 milli amps out, but display shows increase in milli amps , and err6 displays, let me know how to remove the err 6.

2268

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Reason for capillary type dp level transmitter fluctuation

1983

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-/5A. What is the meaning and limitations of this in energy meter constant. It is a 3 phase LT Energy Meter. If this Energy Meter is connected through a CT of ratio 200/5 Amps, then what is the multiplying constant and how its will be calculated.

2459

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I am teja. I am studying Msc(tech) Electronics and Instrumentation (3years course) in Andhra university. But my course is not recognised by UGC and AICTE. Please tell me the job opportunities after this course. And i fineshed PLC course in IGIAT ,Vizag.Also complted my short term coure in SCADA, Seimans WinCC in ATI,Hyd.After Msc can i join Mtech for good job? or phd. How i can get good job in INdustrial Automation Side. Please give replay.Because this is my life matter.

2088

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How the sizing of the analog signal cable is calculate?

2530

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send me model hpcl questions pleas..........my mail id mohideen.dharvesh@gmail.com

2228

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Please asked me How calculate DCS controller memory.

2780

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

3185

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what is difference between fork type and capacitance type level switch. where it is using

2396

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what would be the minimum flow rate that we can measure on rotameter..?

2100

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We are using Rosemount 5400 series Radar Level Transmitters in all types of Sump Applications having oily water hdrocarbon petrochemical nature. What we are facing the problem frequently is that always getting reading frezzed at some value. If we do power recycling , sometimes it is working . then making same freezing problem. If anybody faced before such type of problem and also having solution , Please give the answer.

2328

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what is stroke check for field instument transmetter's & AOV's

2200

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Calculate the maximum pressure drop that can be allowed to occur across a control valve, so that we can prevent cavitation / flashing from occurring. Use the following formula: Δ P allow = Km (P1 – PvapourA) where, Δ P allow - the maximum allowable differential pressure for sizing purposes, or terminal pressure drop; Km- the valve recovery coefficient from the manufacturer’s catalogue; P1 - absolute inlet fluid pressure; PvapourA - absolute fluid vapour pressure at the inlet temperature; Use Atmospheric pressure = 101.3 kPa, P1 = 1200 kPa(g), PvapourA = 4 kPa, KM = 0.72

2218

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