what is the difference between Feedback controller and Feed
forward controller. and when it is to be used.
Answer Posted / muslim
feedback controller: to monitor the controlled variables
(pressure, temperature,..) and feedback the measured value
to the controller to be compared with set point within the
controller , and finally to give corrective signal used to
stabilize the control loop.
feedforward controller: to monitor all loads that influence
the process.
theoritically we have to monitor all loads, but practically
it's impossible .. as there's unmeasured disturbances (like
pipe fitting leaks, composition change ,..) that can't be
predicted.
so if we are to make a complete feedforward control so we
have no feedback mechanism and so we will have a non
disturbed process, which is impracticale.
practically we have feedforward in conjunction with
feedback control , which enhance the loop stability.
| Is This Answer Correct ? | 15 Yes | 3 No |
Post New Answer View All Answers
what is controlling card in dcs? how u measure dcs memory?what is bus in dcs?how u know dcs speed n ehternet speed?
why we are using magnet for calibration of gas detector?
Why even multiple power supplu r used in instrumentation system?
how can i calibrate the temperatuture gauge used by temperature bath(dry block) i mean step by step procedure?
what are the documents(Construction point of view for a process plant) submitted by contactor initially entering in to new site for client?
how will you segregate the alarm levels in alarm management system during factory Acceptance Test
Regarding , there is an air cooler which control the fans(50% of AV FANS) by temperature in outlet , and the louver of Air cooler is controlled by HIC from control system , So if on Air cooler we will consider 2 individual I/P converter or positioner?
our kks tagging is crossing more than 12 character please suggest how to take tags in the DCS
DEAR SIR/MADAM MY NAME IS ARKAPROVA BHATTACHARYYA.I AM A FRESHER INSTRUMENTATION ENGINEER.CAN YOU PLEASE SEND SOME QUESTION PAPERS OF GRADUATE ENGINEER TRAINEE EXAM OF DVC(DAMODAR VALLY CORPORATION).MY EMAIL IDs ARE arka_aec@rediffmail.com.
what is a vortex flow meter,mass flow meter and electromagnetic flow meter.particular use of this.means in which condition particular meter is used.
Is it ok, to use non-contact type Radar type LT, on a tank that is half circular from the bottom side? If yes the, isn't the waves gonna bent in other directions?
1.what is controller proportional gain 2.what is the controller intergral action time. 3.A proportional plus derivative controller that has a proportional band of 20% and a derivative action time of 0.1 minutes. Construct the shape of the output waveform for the triangular input if the input rises and falls at the rate of 4 units per minute.
What is the working principle of the magnetic meter?
how many types of viberation transmitter and how to calibrate and where use of vibration transmitter
I want to buy a seal kit of a pneumatic power cylinder.But I don't know it's specification.So please help me to know its specification.