Control.com - Nerds in Control

My final year project is to design a microcontroller based digital DC motor speed controller where I am assigned the software part...

I plan to use the 16F877 microcontroller from microchip. My problem is I'm new to it and I don't understand how I can control the voltage and get my desired speed of motor. How how does the feedback circuit from motor interact with the microcontroller as a closed loop system?

Isn't that what you were supposed to have learned? I would expect you have books to read.

Regards
cww

Dear kasturi,

The Point that Mr. Wuollet is making (albeit rather brusquely*) is that the question you are asking is rather fundamental. It seems you're asking, "what is a feedback loop?" If that is the case, then you do have some reading to do. Here are some suggestions:

1) "Schaum's Outline of Feedback and Control Systems" (ISBN: 0070170525). This will bring you up to speed on feedback control theory, and it is cheap.

2) "Automatic Control Systems" by Benjamin C. Kuo (8th edition) (ISBN: 0471134767). This title covers more topics and bridges the gap between theory and implementation. Like most textbooks, it is expensive. Look for the earlier editions.

3) "Microcontroller Based Applied Digital Control" by Dogan Ibrahim (ISBN: 0470863358). Dr. Ibrahim will show you exactly how to construct (and program) a feedback control system using none other than the 16F877.

Even if you have taken feedback control theory classes, making the transition from theory to practice can a bit intimidating. So don't feel bad if you're having problems understanding how it all fits together. You'll figure it out. Creating your first real feedback control system is really exciting, so have fun!

A few hints:
1) Use the PWM module along with an H-bridge to control the power to the motor.
2) The CCP module with a Hall effect or optical sensor may be used to calculate the motor speed.

Hope that helps,
- Sean Dugan

thanx a lot for the info...
infact i did a lots of reading n now im progressing wit my programming on PIC16F877.
But my progress is so damn slow as im not good in coding and my codes are alwys having error...
i realy need help in this. can any1 kindly help me out?

Hi,

I am ravi chandar doing my B-Tech IV year. Hey, will you first please explain to me about the project you going are to do, in that what you aim to do? Anyway, I have already completed the project MICRO CONTROLLER BASED DC MOTOR SPEED CONTROL USING PWM TECHNIQUE. I hope you are doing the same. If so, I can assist you in what to do. If not, I am really sorry, but the ATMEL AT98c52 IC is very fine to use.

I believe you meant Atmel 89C52 and not Atmel 98C52...!!

au revoir
Rahul