Answer Posted / www.islamqa.com
Actually we can make it simple:
# P:
it's a controller gain which modify the controller o/p
proportional to the error.
# I:
it's a controller gain which modify the controller o/p
proportional to the integral of the error.
# D:
it's a controller gain which modify the controller o/p
proportional to error rate of change.
We have 4 parameters in our control loop to focus on:
1 - the rise time: the period of time during which the pv
get 90% of the desired sp value
2 - max overshoot
3 - settling time: the period of time during which the pv
get the desired sp value and saturate.
4 - error/offset
we can get it clear from this pic:
http://controls.ame.nd.edu/ame437/S2003/hw1/specifications.j
pg
Now we will take a look about the effect of each controller
gain on these parameters:
# P gain:
decrease rise time
increase max.overshoot
increase settling time
decrease error (but not eliminate)
# I gain:
decrease rise time
increase max.overshoot
increase settling time
eliminate error.
# D gain:
no effect on rise time
decrease max.overshoot
decrease settling time
decrease error.
the previous is guidelines to be in background while
dealing with PID,but they are not sharp limits.
Regards,
Ahmed Sabry
Control and Instrumentation Engineer
GPC - General Petroleum Company
ahmedsabry.online@gmail.com
CELL.: 00 2 0121367310
| Is This Answer Correct ? | 4 Yes | 1 No |
Post New Answer View All Answers
the whole paper was based on Transducers..questions like define repeatability, error,accuracy,precision..den there were many q. on the conversion of Pa to mmHg and other units.. also..der wer few Q. on some level sensors(with diagram)
How ejector(or)evactor air pump is working in thermal power plant?
why we use the ac supply load cell>?can we use the dc supply load cell?advantages and disadvantage of the ac supply load cell?
all types instrumentation questions want
What are de-saturators?
CONTROL VALVE OPERATING IN MANUAL BUT NOT IN MANUAL. WHAT SHOULD BE THE PROBLEM ?
whatis range of marcury filled tempereture gague
With N nodes and B branches what will have a network ???
what can of fault ofently come in vibration mesurement?
I have 0.75mm sq multicore cable (IS type) , can use instead of same type but 1.5 sq mm cable ? Note : The distance is around about 150 meter.
applications of plc in printing and packaging?
I want to know the questions asked in ONGC interview(after being selected in the written exam) for Instrumentation branch.Kindly help.
What care will you take in the installation of control valves,SCADA,DCS and FOC in Oil and Gas Project?
what are the values of fuel flow rate in various places in boiler.
Draw bode plot of any transfer function. Why is plotting bode necessary?