Dither in PWM

Thread Starter

manuatl

Joined Sep 25, 2015
2
Hi,
Can any one please share some useful document on adding dither to PWM, for proportional control valve.

Rgrds,
Manu
 

crutschow

Joined Mar 14, 2008
26,789
I assume the dither would be just to add a small AC signal to the DC control signal value going to the PWM modulator.
Where did you read about adding "dither" to the valve signal?
 

BR-549

Joined Sep 22, 2013
4,938
mcgyvr, thanks for that first sheet. I bought that board, but haven’t started on it yet. The manual has 1700+ pages.

I read those other links.

I know nothing on this, but if the TS didn’t want the software solution, could one separately pwm the other end of the solenoid for dither?

Both pwms would be independent and adjustable.
 

dannyf

Joined Sep 13, 2015
2,197
Can any one please share some useful document on adding dither to PWM, for proportional control valve.
If you were to run your PWM at 4/256 duty cycle 50% of the time, and then 5/256 duty cycle another 50% of the time, you have effectively had a 4.5/256 or 8/512 duty cycle -> dithering.

Algorithms that accumulate historic errors (PID for example) are inherently dithering.
 
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