My research says that the K40 stepper motors each have different current limitations, the Y motor limited to 1A, and the X motor to 0.48A, so I have reduced the driver voltage accordingly.
Examination of the limit switches (mechanical)shows that they are wired as normally closed, so have set GRBL $5 to 1, inverted.
All of that, just to introduce my issue.
On power up, the machine does nothing until I connect Lightburn the machine tries to home, but just seems to move (or vibrate) back and forth in small noisy increments along the X-axis as shown in this short video.
Which is why I am appealing to you for help. Does anyone here have comments, questions or perhaps an answer that will help solve this problem?
Regards,
Don
first thing I would do is unplug the 2 motor connectors from the MKS board and then using a DMM I would ohm out each motor looking for each A and B pairs. I would do this at the clamp screws of the Middleman Board. Once A and B coils have been identified on a motor, check the MKS DLC32 v2.1 board schematic(or labels) to see if you have the 2 coils connected to the proper A and B pins of the connector. If they are, then reverse the A coil wires at that Middleman Board for only that motor, plug back in only that motor’s connector to the MKS board and test if the movement is smooth. If it is and the movement is in the wrong direction, swap the A and B pairs at the Middleman Board.
Well, I measured both coils on each of the motors, and identified that the first two pins are for the first coil and pins three and four are for the second coil of each motor. The Y-axis measures 3.9 ohms for each coil and the X-axis measures 20.2 ohms for each coil. I expected the difference, as max amperage on the X motor is 0.44 A and on the Y motor is 1 A. I think that I was confused by the varying terminology used to identify stepper motor coils. The M2 Nano board markings indicate that the first tow motor pins are A+ and A-and pins 3 and 4 are B+ and B-. The MKS DLC32 v2.1 board shows the first two pins as 1B and 1A ( coil 1) and pins 3 and 4 as 2A and 2B (coil 2). I now believe that the M2 Nano board markings indicate that the A+ and A- pins are coil 1, + and - sides and the same for the B+ and the B-, pins 3 and 4. So I moved the wires on the Middleman board to correspond with the logic I identified. I seem to have created a monster, as now the stepper motors do nothing when the board is powered up and given the command to home.
I wondered if I had bricked the board, so I moved it to a CNC machine that I have, changed the settings for the CNC and it works with that machine. So not bricked, but I am at a loss as to where to move next to troubleshoot this issue. Any suggestions or comments would be appreciated.
I am will try to including my settings here in an attached file, as I expect that I may also have a problem lurking in the settings. Note the alarms indicated at the end when I tried to Home and move the Axis using LIGHTBURN buttons.
So now that you believe you have the coils identified and wired to the correct pairs of the MKS, if you don’t have movement then swap one coil pair on one motor. Hopefully that motor now moves. If it moves in the correct direction go to the next motor, if it doesn’t move in the correct direction then swap the A and B pairs keeping the same polarity so it then goes in the opposite direction.
Thank you again for taking the time to reply to my issue with accurate advice! It turns out that I was focusing only on the forest and the problem was with the trees. It turns out my [problems were a combination of a bad TMC2209 driver and a couple of bad wire connections. All is squared away, and now I can tackle the mirror adjustment and replacement and try out the LIGHTBURN software.
Regards.
Don
