Help needed with calibration.

[Terry1956]

Hi, today I watched Marty’s video on how to calibrate the axis. However for some reason it’s not working for me.
Here is what I set up. I am using a closed loop stepper driver and motor. The driver is a CL57T with matching Nema 23 motor.
Within the acorn wizard I have made the following settings.
Steps per revolution = 200 not using half steps. And I believe that encoder steps are 200 for this driver, maybe wrong.
Turns ratio = 6 It takes the motor 6 turns to move the bed 25mm at a 1 to 1 ratio. There are 6 threads per 25mm on the leadscrew.
I set max speed at 5000mm
Max jog at 4500mm
Slow jog at 270mm
The speed of movement looks and sounds ok.
However if I enter the command G90 X40 G0 the machine only moves 6mm not 40mm as per command.
If I use Marty’s calculator it gives me a turns ratio of 1.5 and then nothing moves.
What am I doing wrong

[ShawnM]

Your steps per rev are not 200, that’s a spec for all stepper motors. You can’t have a setting less than 1600 for Acorn. Set your steps per rev to 4000 and start there. Anywhere between 2000 to 8000 is good for closed loop steppers. Match the drive DIP switch setting and in the wizard. You can try 6 for your overall turns ratio and start there. After that only adjust your turns ratio to dial it in. All this is in the LATEST install manual. You are probably watching a video that is 5+ years old and no longer relevant.

[Terry1956]

Thanks shawnM

[suntravel]

These Steppers are running best set to 4000 Steps, maybe because this is the build in encoder resolution.

Uwe

[Terry1956]

Just found the problem. I got the motor to thread revolutions count wrong. I must get some light in the workshop, or better glasses.

[ShawnM]

Just found the problem. I got the motor to thread revolutions count wrong. I must get some light in the workshop, or better glasses.

You may have found a problem but you still cant leave the step at 200, that is not correct. Set the drive and Acorn to 4000 as Uwe stated. He's used these before with great success.

[Terry1956]

I have reset the steps etc. and have managed to get the calibration down to a few thousands of a mm. I just need to sort the backlash out now. But I think I will add a few lights over the milling machine as it’s winter here in the U.K. and very dark days.

[ShawnM]

I have reset the steps etc. and have managed to get the calibration down to a few thousands of a mm. I just need to sort the backlash out now. But I think I will add a few lights over the milling machine as it’s winter here in the U.K. and very dark days.

Glad you got it sorted out. Get your turns ratio dialed in the best you can first and then determine your backlash and set those values in the software.

I tried building a CNC router once with my eyes closed and it didn't go very well.