Answer / karthika

Tunning is a process in which we adjust the controller parameters(Kp,Ki,Kd) so as to obtain desired performance of the controller.

different tyes of tunning:-
1. Zigler-Nicholes method
2. Cohen Choon
3. 1/4 decay ratio

Answer / chhote lal

by the help of P we calculate the error signal
Error signal=SP-PV (How Much)in the timming of pid tunning.
By the help of I we Remove the offset error-it will decide
how long the error exit in the cycle inthe timming of pid
tunning.
And by the help od D we fasten the control action-it will
decide how fast the control action to remove the error
without any overshoot for failure cycle.
at last
P=How Much(present)
I=How Long(past)
D=How Fast(future)

Answer / 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

Answer / sumit sharma

pid is proportional integrative derivative
pid is a closed loop system which is used for error checking of analog devices only, it cant used on digital devices.
pid consistes of
kp proportional
ki integrative
kd derivative
in pid tuning first kp,ki,kd is taken as any integer and then error is checked by the pid formulae
if there is error then the values of kp ki kd can be changed to give the error 0

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.

0 Answers   Sabic,

---

what is coriolis principle for mass flowmeter?

5 Answers   ABB,

---

how to wire from pressure transmitter to marshalling panel and panel to controller and controller to dcs plz give the answer with example .

2 Answers  

---

During valve sizing from all calculation you got flow coefficient CV 12,than what it means? like for selecting pressure transmitter if your MAWP is 12 bar than you select a capsule of max. 20 bar which cover your mawp 12 in same way for selecting control valve If CV is 12 than how we use it in selecting valve??????

1 Answers  

---

What is deffrence between Battery and capacitor

3 Answers   Siemens,

---

what is Best Among SINK Or SOURCE Type Design In Digital Signal, Either Iput Or Output? WHY?Can any one..

0 Answers   Accer, Reliance,

---

Why trim span ? How?

0 Answers  

---

what is the difference between Feedback controller and Feed forward controller. and when it is to be used.

3 Answers  

---

what is the function of boiler in plant?

2 Answers   Maden,

---

What are the most frequent problem faces with Vortex flow meter?

1 Answers  

---

in split range control valve,two valve should be in two different line and that should have some distance,and we have only one positioner feed back link.so how we connect one feed back in two control valves?if you have picture please forward me.my email id kb.syamkumar@gmail.com

2 Answers  

---

How to calculate the range of level transmitter?

4 Answers   Wika,

---