Will move only DIR High direction?

[thejinn13]

Hey you all,
After the first success on connecting and running the calibration without any problem, I now cannot find the solution for adjusting the direction of the stepper. In short: it won't move backwards, a.k.a. the DIR = LOW wont move, but just stall.

The circumstances:

Arduino UNO sends commands to the S42B-V2.0 via digital Pins D2 (En), D3 (Dir), D4 (Step). Further the UNO provides 5V to the 5V COM of the S42B as also common for other drivers.

There is no load on the stepper. If rotating, it consumes about 200mA. I use the following sketch from ##13 (comment)
sketch_jul20a_BigTreeTechS42Btest.txt
Note, that I sent quite slow pulstrains.

I changed various Dip-Positions on the S42B-V2.0. On my board: Dip No. 2 accounts for Closed/Open Loop. The problem persists in Open Loop mode.
I checked the stepper for a broken coil. However, both phases have 2.2Ohms.

To spice it up:
Adjusting Enable on the Stepper (OLED) to "!Enable" won't work, too. The motor will also only start on HIGH with "Enable" activated.

I dispared already, nothing would make me happier than some you capable people would find an obvious mistake.

best

[thejinn13]

Dear who it may concern,

I figured the problem. Of course it turned out to be a novice error.

Please make sure, that you properly defined GND in the above sketched circuit. It is of major importance the GND Arduino and GND S42B have the same level.

My floating lab-supply of course did not share a GND with the Arduino. Therefore the level of the control Pins for STEP, DIR und EN were quite undefined. Connecting a GND Pin of the Arduino with the negative pole of the lab-supply solved the problem.

Interestingly, other drivers (TB6600) do not have this problem. It could be from separated rails or just a housing kept at neg. lab-supply.