[German0]

Hello everyone,
My name is German, I am a teacher at a technical school, and I am restoring a cnc milling cutter from the 90/00s.

The electronics are obsolete, as well as the control software, since the PCs to use it no longer exist. Therefore, I decided to implement a control through Arduino with CNC Shield v3, using GRBL v1.1 as firmware and Universal Gcode sender for control.

The stepper motors are LIN Engineering model 5718M-05D-01 of 2.0A, and they work perfectly individually controlled, with a time between steps of 3 ms.
And here my problem, the GRBL does not allow me times between steps greater than 255 us.

My query then is:
Does anyone know if it's possible to change these microseconds to millis? if so, how?
Do you know of any other firmware that I can use that allows me to work with intervals close to these 3 ms that I require?

Thank you very much for your help, my students and the school will appreciate it.

[hfjbuis]

The max step frequentie on a grbl uno controller is 33kHz. To be safe, I don't go faster than 10kHz. I am not sure about the slowest speed, but 1Hz should not be a problem.

You need to setup the grbl controller
$0 the minimum step pulse time
Set it to 10 us to be safe

$100, $101, $102 steps/mm (travel resolution)
This depends on the pitch of you spindels, stepper configuration and gear ratio

$110, $111, $112 the max rate
Keep this value as low as possible. Slower speeds results in lesser damage when things go wrong.
The max value depends on how fast your steppers can run under load.
$120, $121, $122 the accelleration
Keep this value as low as possible. When all is working properly you can increase this value until you start losing steps. Than reduce it by 50%

For more information, GRBL has a great WiKi https://github.com/gnea/grbl/wiki

[German0]

The problem was solved by setting parameters 110, 111 and 112. I understand that by limiting the speed, the interval between the steps is kept sufficiently spaced.

Thank you very much for your reply.

[hfjbuis]

German,

Great to hear it is working and thanks for the feedback.

Huub