# erickone96

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8

## Posts posted by erickone96

Sure thing. I will do that as soon as I finish it.

Erick

Nevermind, I was reading the rpm value from the register where I was sending it. I changed the Serial.print(RPM) and didnt show any 0 anymore lol.

Thanks though!

Hey Jack,

The decoder is giving me a good reading of getSpeed function type 0 (96MHz clock ticks for 5 A_clock pulses). I am able to compute the RPM and then average 40 readings giving me a pretty good and fast RPM reading. The only issue now is that I get an average RPM = 0 everynow and then. Not sure what could be causing it since decoder seems to be working properly.

I'm using this method to average the RPM: https://www.arduino.cc/en/Tutorial/Smoothing

And this is how Im computing the RPM for example:

Robot_Control_Library.getSpeed(0): 37366

Time for the 5 pulses: 37366 x 10.4ns

5 pulsles out of 1000 ppr = 0.005

V = 0.005 rev / 387us = 12.9 rev/s x 60 = 774 rpm.

In my code, Im computing it as:

Im guessing that the prob is because of the large numbers in the computation ?

Any suggestions ?

Thanks,

Ruben

Hey there,

I have been working in a dc motor control project. So far I got the motor running open loop pretty good (clockwise and counter clockwise), and now I wanna implement a closed loop speed feedback. I tried using the quadrature decoder to read the pulses coming from an quadrature incremental encoder. So this is what I read at approx. 1720 rpm

Pulse Count
33133033
Speed
-17034
-36.43

Pulse Count
33130475
Speed
-17296
-36.16

Pulse Count
33127931
Speed
-17003
-36.05

Pulse Count
33125396
Speed
-16801
-37.98

Pulse Count
33122854
Speed
-17035
-36.73

Pulse Count
33120307
Speed
-16784
-36.69

It is negative because its rotating counter clockwise. Why is it too inaccurate? I have attached my project just in case someone wants to take a look at it.

Thanks,

P.D. The motor runs at 4000 rpm max. Encoder specs: 1000 ppr. A, B, and I.

5. ### PWM generator

Hi Jack,

I just figured out how to change the frequency of my pwms. I saw in the vhdl code that  [ freq = CLK / (2^PWM_width)]. Thank you so much for replying so quick though! Have a great day!

P.D. I was using the RCL_PWM_x48.

Regards,

Ruben

6. ### PWM generator

Hello,

I'm using the PWM generator block successfully, but the PWM signals have a frequency of about 375KHz (way too fast for my application). Is it possible to change the frequency of the generated PWM signals without messing around with the VHDL code? I'm not very familiar with VHDL. I'm generating two PWM signals, one is the complement of the other (while 1 is high the other one is low), that I will be using for controlling a DC motor so a reasonable frequency would be between 500Hz and 20KHz.

thanks,

Erick

7. ### Modification RCL_PWM_x48

Hello,

I'm using the PWM generator block successfully, but the PWM signals have a frequency of about 375KHz (way too fast for my application). Is it possible to reuse that code for setting up a different PWM generator that uses a exteral clock that may allow me to generate PWMs at 1/100 frequency ? I'm not very familiar with VHDL.

thanks,

Erick