Issue reading pulses from DC motor to arduino

Using Arduino Motors, Mechanics, Power and CNC
1

Hi,

I am working on a project that requires me to calculate both speed and position of a DC motor. I am using an Arduino Uno, TB6612FNG driver and a 34:1 6V HP gear motor 48 CPR. I am trying to read the pulses and design the project using Simulink.

The motor used is Motor. According to the documentation of the motor, I should be receiving 12 pulses per revolution ( only reading channel A). However, when I try to read the pulses using an Arduino digital input block (pin 4) connected to a scope, I'm only receiving around 4 pulses per second which is well below what I'd expect.

I'm not quite sure if I've configured something incorrectly or I am misinterpreting the scope, but I'm hoping for some clarification or a reason to why this may be the case.

let me know if anymore information is required that i may have missed.

Thank you for your time

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2

You need to learn what a "quadrature encoder" is. Ask Oncle Google.
Reading 4 pulses per rev is correct reading only one of the two signals.

3

Sorry. But shouldn’t it be 48 PPR for both channels and 12 PPR for a single channel. Also I am getting much more than 1 revolution per second

4

This link shows the encoder output.

How are you counting revolutions? From the motor or the output?

5

I am manually counting them while using the scope block in simulink. The example given is using an oscilloscope

6

Could you please further explain what you meant by 4 pulses is correct? I’m quite stuck on it.

7

You have misunderstood that encoder. Please post a link to its datasheet.
Quadrature encoders use 2 channels of pulstrain being shifted 90 degrees. You need to use both channels.

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Look at the oscilloscope picture! That's how the puls train looks like.

10

Can You post schematics of Your test setup, and the code used?
You say You get 4 pulses per second. That doesn't tell much. What is the speed of the motor?
Check pulses per revolution instead.

11

The code, posted using code tags, a clearly labeled, hand drawn wiring diagram, and a link to the motor driver.

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