Dc motor noise filtering techniques for micro-controller.

[irfan ahmad]

HELLO GURUS.
recently i have faced a problem about high noise of a high speed dc motor.

.
I was trying to implement pid controller using arduino, with 500hz pwm frequency.
Arduino -->> optocoupler-->>l298 (motor driver)-->>motor-->> cutt sensor(for rps) -->> Arduino (feedback).
rps= revolution per second.
but arduino was taking random readings :bsdetector: :twisted: :bang::bang::bang: .
then i decide to separate motor power supply and Arduino power supply.
(seperate Ground), but problem was still there.
then an idea click in my mind and i put a filter on motor wire (like toridle transformer ).
this one.

now magic was start :grin::grin:.
Every thing was working fine.

then i have tested the project with filter and without filter .
without filter everything goes wrong:bsdetector::bsdetector::bsdetector::bsdetector::bsdetector: .
with filter everything works fine.:smile::smile::smile::smile:

then i find one more technique . this
.
.project is complete and successfully working.
but i want to know your opinions. :?::?::?:

 

[GrandAlf]

Good to see you have resolved the problem. There are many ways other than the ones you have used but no one solution. Methods include Board layout with common ground point, psu decoupling, VDRs across motor, inverse parallel and series diodes, faster the better, shielded cable/motor etc. Good practice if any interconnected equipment is all grounds back to one single point rather than looping. Eliminating interference is a common cause of frustration when designing new projects, can be very difficult to solve sometimes, but you have the right methodological approach.

 

[irfan ahmad]

Thanks for your reply.
i was using this driver **broken link removed**
i am wonder .
even i have connected full bridge across motor , rc filter , isolation and
no effect.
after connecting this Amulet (filter ) everything is working fine.