Set Vref for MKS DLC v.2.0 with TMC2209

Lasers
1

Hi,
I try to build laser engraver.
Parts

  • 2x NEMA17 1.5A
  • 2x step drivers TMC2209
  • MKS DLC v 2.0
  • power supply: 12V 8.3A

Software
OpenBuilds CONTROL - Machine Interface Controller

When I connect engines to board it moves but when I use belt to move caret or just touch a pulley engine stop moving.

I try to set Vref using stepper driver screw but value oscillates around 0.10 - 0.14 V.

I search websites and it should be near 1.5V reduced to 70% for safety (= 1.05V) but its hard to get even near that value.

I measured it with only power on (without connected USB and engines) between pin EN and GND or stepper screw and GND - values was the same.

Is there another switch or screw to change this volume?

Thanks fo any help

2

Can you show pictures and point to what you were adjusting and measuring on it? I think there’s a misunderstanding here but I’m not quite sure what it is, and a picture might help resolve it.

3

Sure!
but there is need some explanation.
Today I noticed that one wire from electric meter was almost broken I solder it and now it looks like it works - I mean Vref.
I set it to 1.08V (image). Between GND and EN - 5,07V

Screenshot_8
Screenshot_8918Ă—724 140 KB

Here I placed 2 movie, which I was recorded to show general problem

[2 new photos added to shared album] Laser

without belt engine move byt when belt is put on is move step forward and step back.

I don’t have an idea what is wrong…

4

Well, that explains the problem with measuring the voltage! But it means I don’t see an easy answer.

I think that the “70% for safety” is probably related to confusion over RMS vs. peak current. If should be safe to run the steppers up to their rated current, but they should at least function at 1A.

Do you have any other stepper motors or stepsticks to swap to compare?

5

Ok,
I have two stepper motors both have the same issue.

When I replaced stepsticks with A4988 it getting shaked (fast forwart and backward)

Last movie (with comment Stepstick A4988)

[3 new photos added to shared album] Laser
6

The only time that I’ve personally seen something like that, I had a bad connection.

Just making sure, you have the 12V connected when testing and it’s not trying to drive off the 5V USB, right? Vmot to GND is 12V at the stepstick?

7

1st - yes - only power supply is connected
2nd - between both stepsticks are ~11.95V

IMG_20210504_225746
IMG_20210504_2257463000Ă—1628 514 KB

8

Sorry for long quiet from my site.

I tested many possibilities I finally it starts to work.

The answer for the future looking…

Try to connect wires in different ways.

My Solution:
Coil 1 - 1A 1B
Coil 2 - 2A 2B

I have special wire to connect NEMA with board and its not prepared for my stuff, so it directed my thinking in wrong way…

1 Like
9

Ah, a different way of having a bad connection! :relaxed: