[Solved] Using the OpenBuilds BlackBox CNC controller with SOLO for controlling the spindle

Hi @gs76,

Unfortunately, the link provided is broken, can you put the direct link it the user manual of the device here, please?

Regards
Milad

Hi @Milad,

I hope this works.

https://docs.openbuilds.com/doku.php?id=docs:blackbox:connect-vfd

@Milad,

I see the link still did not work.

Please see the PDF of the page attached.

Thank you

@GS76

@gs76, 

At analog input of S/T on SOLO UNO, you can only apply a maximum of up to 5V, it seems this module can generate various voltages up to 10V, so you need to somehow put the max speed of your motor in a way the module generates 5V, surely before connecting that output to SOLO, first you need to measure the voltage with a volt-meter and make sure it doesn't exceed 5V.

let me know if you have other questions.

Regards

Milad

@milad 

Thank you for your support, as always.

Regards,

@GS76

@milad 

I have asked the manufacturer of the CNC controller if there are other options and they think the "PWM" option may be possible.

Please see the attached document in the highlighted section in "2g" of the CNC controller's documentation. Do you think this may be an option?

Hi @gs76,

The highlighted section says the module supports a 5V leveled PWM pulse for the output, so if the desired speed is defined by the duty cycle of that PWM pulse, then it will totally match with SOLO, meaning that if the speed increases we are expecting to see some increase in the PWM duty cycle and vice versa, the frequency of the PWM though can be any thing greater than 5kHz, let me know if you need more information.

Regards
Milad

@milad

Thank you for your reply.

I will check with the CNC controller board manufacturer if their specs match your requirements.

@GS76

@milad 

As per our previous communication regarding using a PWM output from a CNC controller to control the analog input S/T of the Uno to control the speed.

Could you tell me how the connection would be configured with UNO, i.e. would it be connected to the S/T and ground somehow?

I just want to understand the connection.

Thank you again.

Hi @gs76,

Posted by: @gs76

would it be connected to the S/T and ground somehow

Yes, you just need to connect the PWM output of your CNC controller to S/T input of SOLO, besides you need to connect the Ground of your CNC controller ( the GND ) to the GND of SOLO on the same port that S/T exists ( the green 5 pin Pheonix connector)

Let me know if you have other questions.

Milad

@milad 

Thank you for your valued response.

Much appreciated.

@Milad

How are you?

I have purchased and got up and running the following GRBL CNC controller.

BlackBox X32 | OpenBuilds

It has a PWM output (0V-3.3V).

As previously discussed (please see the above chat), these outputs can be connected to the Uno via GND and S/T.

I connected the UNO to the above controller as I described. It worked once connected. I, however, have several questions.

1. The controller allows the PWM frequency to be set. I have currently set it to 80kHz. What is the recommended frequency?

2. Once I change the speed of the spindle with a CNC command, I find that the motor runs, but it would sometimes slow down and then go back up to speed and then, after time, slow down again etc. It is random. Is this related to further adjustments on the UNO?

3. I use a brushless motor with no sensor/hall connection. How could I reverse the direction of the motor? Could I swap the A and C connections?

Thank you for the help.

Regards,

GS76

Hello @gs76,

Posted by: @gs76

↑

1. The controller allows the PWM frequency to be set. I have currently set it to 80kHz. What is the recommended frequency?

This is totally fine, any frequency above 5kHz should do the job, and its value of it is not important.

Posted by: @gs76

↑

2. Once I change the speed of the spindle with a CNC command, I find that the motor runs, but it would sometimes slow down and then go back up to speed and then, after time, slow down again, etc. It is random. Is this related to further adjustments on the UNO?

This might be due to the Speed controllers Kp and Ki gains, where in Analogue mode, you set them using the Potentiometers on board, so maybe you can increase a bit the Kp value to see if that behavior becomes better or worst.

Posted by: @gs76

↑

3. I use a brushless motor with no sensor/hall connection. How could I reverse the direction of the motor? Could I swap the A and C connections?

 

Yes, this should work, please test it and let me know ( pls make sure you turn off the unit before swapping the wires)

I will remain available.

Milad

@Milad

Thank you for your replies!

It is much appreciated.

An additional question:

1. Must I update the drivers on the original UNO board?

2. What is the difference between the original UNO and the UNO V2?

Regards.