Very strange behavior, CoreXY with external drivers

Capricorn

@veti

hmmmm... now i´m unsure myself.... maybe dc42 can light this issue up?

Capricorn

@dc42

To the question of groundloops...

is my power distribution ok?

jhonf441

@capricorn said in Very strange behavior, CoreXY with external drivers:

@dc42

to clarify how my extern drivers are connected:
all Step+/Dir+ from the ext. drivers go to +5V.
all Step-/Dir- from the ext. drivers go to the corresponding pins on the breakout board

I can not read in its description, where the EN pins of the external drivers are connected.

@capricorn said in Very strange behavior, CoreXY with external drivers:

@dc42

To the question of groundloops...

is my power distribution ok?

GND (-) from all sources should be a common point, to that the logical levels that reach the external drivers are measured with respect to a single GND of the entire system.

dc42

@capricorn said in Very strange behavior, CoreXY with external drivers:

@veti

not suitable for me, because i have no duex2 oder duex5 board. i have the duet2 ethernet and the expansion breakout board. the breakout board is only connected by the 50Pin connector

Can you provide photos of your wiring between the expansion breakout board and the stepper drivers, so that I can check it?

@veti said in Very strange behavior, CoreXY with external drivers:

it would still cause a grounding loop.
https://en.wikipedia.org/wiki/Ground_loop_(electricity)
there is also a very specific warning for the duet where you have a separate 5v supply via usb.
see
https://duet3d.dozuki.com/Wiki/USB_ground_loops

Should not be a problem if the 5V and main PSUs are in the same case, fed by the same mains cable.

Capricorn

@dc42
I think you won't see much.

Capricorn

@dc42

Capricorn

@dc42
I hope you can see anything. I'm 100% shure, there is nö mistake in the cabling. I checked every single connection more than once, incl. with Multimeter.

jhonf441

@capricorn You need to connect each ENABLE signal that comes from the breakout board to ENA (-) of each driver.

Capricorn

@jhonf441
No, not necessary and my drivers don't work at all, when connected.

Capricorn

@dc42
Maybe this helps to localize the problem :
I measured the resistance between the different
Step- Ports:
X>Y = 9.74 kOhm
Z>Y = 9.74 kOhm
X>Z = 3.30 Ohm!!!
Maybe the Breakoutboard is damaged?
But i'm uncertain, because this measurements are always the same, no matter which combination of Ports 5-9 I use.
Not connected to the Breakoutboard the resistance
in each xyz combination is 7.75 kOhm (because of the common 5V line to each driver)

dc42

I was already thinking that it's time to try a new breakout board and ribbon cable. Please ask your supplier to replace them. https://www.duet3d.com/warranty

Capricorn

@dc42
OK, i'll try that.
Thank you so much, I will report if that works.
Meanwhile I finished cabling and everything works great , only the Motors

Capricorn

Newest update:
Last Monday, i ordered a new Breakout-Board at a German supplier. They confirmed my order and told me, it's on stock and delivery time 3-4 days. Nothing happend since then.
So today i lost patience and did some further tests.
Result is, i desoldered the 4 75ALS192 chips and connected all the S-/D- to the appropriate ports on the 50-pin connector. Had to change the direction of rotation, and viola', all systems running. Perfect...
Smoothly...
I can not wait any longer, to do my first print. I'm so exited....
Thank you all, for trying to help me with that issue.