Incremental rotary encoder motor help

In summary, the conversation discusses how to calculate the angle change and RPM for a motor using encoder counts and sample frequency. The correct method for calculating the angle change is to divide the encoder count by 128 and then multiply by 360, and the correct method for calculating RPM is to divide the revolutions by the sample frequency and convert to RPM. The example given in the conversation shows that the motor speed would be close to 3000 RPM with a sample frequency of 1Hz and close to 6000 RPM with a sample frequency of 2Hz. The conversation also clarifies how to find the RPM using the encoder count and time.
  • #1
AC130
5
0

Homework Statement


Hi please see the image that I have attached. The text colored in red is the data I need to calculate.

Homework Equations

The Attempt at a Solution


The encoder has 128 counts per revolution
So to calculate corresponding angle change this I what I did
I divided encoder count in decimal number by 128 which gave the number of revolutions, I then multiplied it by 360 to find the angle change

So for example I did
6350/128 = 49.61 revolutions
49.61 * 360 = 17859.34 degrees

Is this method right?

To calculate no load speed RPM, I divided the revolutions by (time*60) to get it to RPM

So for the 6350 encoder count which gave 49.61 revolutions

I did

49.64/(5.25*60) = 0.1575 RPM

Is this RPM calculation right?

For me it looks as if the RPM is well below and so I must have made a mistake somewhere but I don't know specifically where
 

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  • #2
AC130 said:
So for example I did
6350/128 = 49.61 revolutions
49.61 * 360 = 17859.34 degrees
That's correct.

To calculate the speed, you must know the sample frequency. Say it is 1Hz. Then you will have 6350 counts per second.
Convert to RPM. ( 128 counts per rev, 60 sec/min ).

The result is close to 3000 RPM.

If the sample frequency were 2Hz, the motor speed would be the double ( ≈ 6000 RPM ).
 
Last edited:
  • #3
Hesch said:
That's correct.

To calculate the speed, you must know the sample frequency. Say it is 1Hz. Then you will have 6350 counts per second.
Convert to RPM. ( 128 counts per rev, 60 sec/min ).

The result is close to 3000 RPM.

If the sample frequency were 2Hz, the motor speed would be the double ( ≈ 6000 RPM ).

Hi can you please tell me where RPM came from?
I know that it took 5.25 sec for the angle change and so frequency would be 1/T = 1/5.25 = 0.1905Hz

But I don't really know how to find RPM
 
  • #4
AC130 said:
So for the 6350 encoder count which gave 49.61 revolutions
AC130 said:
I know that it took 5.25 sec for the angle change
So 49.61 rev. within 5.25 sec, which gives 9.449 rev./sec ≈ 567 rev/min. = 567 RPM. ( 1 min = 60 sec ).

The RPM's in #2 is just an example, not knowing your mentioned 5.25 sec.
 
  • #5
Ok thanks I understand it now
 

1. What is an incremental rotary encoder motor?

An incremental rotary encoder motor is a type of motor that uses a rotary encoder to measure the rotation and position of the motor shaft. It produces electrical signals that can be used to track the movement and position of the motor.

2. How does an incremental rotary encoder motor work?

The motor is equipped with a rotary encoder that consists of a disc with evenly spaced slots, and an infrared LED and sensor. As the motor shaft rotates, the disc also rotates, causing the LED and sensor to detect changes in the slots. This produces electrical pulses that are then translated into movement and position data.

3. What are the advantages of using an incremental rotary encoder motor?

One advantage is its high resolution, meaning it can detect even the smallest movements and changes in position. It also has a fast response time, making it suitable for applications that require precise and quick movements. Additionally, it is compact and can withstand harsh environments.

4. What are some common applications of incremental rotary encoder motors?

These motors are commonly used in industrial and automation systems, such as CNC machines, robots, and conveyor systems. They are also used in consumer electronics, such as printers and scanners, as well as in automotive applications for tracking the position of car parts.

5. How do I choose the right incremental rotary encoder motor for my project?

When selecting a motor, consider factors such as the required resolution, speed, and accuracy for your specific application. You should also consider the size, power requirements, and compatibility with your control system. It is best to consult with a motor expert or refer to the motor's datasheet for more detailed specifications.

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