MACH3 or DM542A driver or DB25-1205 issue?

[dffang]

Hello All,

I have been been tinkering with building a CNC and have the mechanics of it all constructed. I'm working on the drivers and BOB (interface) and MACH3. I wired the motors and can move them all. My problem is they do not move consistently or predictably. The change direction on their own. for example I hold down the page UP key and the Z motor turns a few to several rotations in one direction and then changes direction. All 3 axis show the same erratic behavior. I wired the BOB with the attached schematic. I and reviewed the wiring and redone it a few times. What is the best way to trouble shoot this problem? Is it a MACH3 issue or a BOB issue or a driver setting issue?

Thanks in advance,
Dave

[joeavaerage]

Hi,
I don't see any pictures attached to your post.

It could be that you parallel port on your PC has 3.3V outputs which is common on newer designed PCs whereas your BoB requires 5V which
was/is the common standard certainly from a few years back.

Do you have a mulitmeter?

Craig

[dffang]

I'm using a uccnc (UC100) to a USB port on a Dell laptop.

As I understand the DB25-1205 manual I need jumpers 1 & 2 installed and 5v & ground from a seperate power source connected. I think my supply is working but will verify with a meter. Thanks.

[dffang]

here's that schematic image again...Attachment 410403

[routalot]

I can't offer too much help with the uccnc part but I did-eventually-get a DM542A and DB25-1205 to work with LinuxCNC.In the course of looking at what the uccnc part looks like and does I found this warning on their website,might it be relevant?Incidentally your images aren't showing.



Be aware that counterfreit fake UC100 motion controllers are sold on e-bay, alibaba, banggood and amazon!

The fake devices will not work with our software!

Please follow this link for more informations: forum.cncdrive.com • View topic - !!!Fake UC100 controllers on e-bay!!!



.

[dffang]

Meter shows I am pumping in 5 V and Ground to the BOB.

I read 2.54 VDC coming out of the DIR+ when moving in one direction and 0.74 VDC when moving in the other direction. But the motor moves several turns one direction and then reverses for a few to several turns and then reverts back to the original direction for a few to several more turns... It seems weird because the voltage stays stable at 2.54 VDC or at 0.74 VDC.

I tried connecting the DIR+ directly to 5 VDC (and to GROUND) to see if that made any difference - it did not ... still erratic and unpredictable as to what direction the motor will turn. I'm pretty decent with electronics but this one has me confused.

I am wondering if I have something messed up in a config of MACH3?

[routalot]

I don't see any mention of a power supply for the DM542A.I have attached a file of the inside of my control box which shows the DB25-1205 at the top,the DM542A controls next down and the 36 volt power supply to the right.As mentioned earlier,I don't use Mach3 but LinuxCNC but the electrical system just sees pulses regardless of the software used.The most significant criticism I have seen regarding the DB25-1205 showed that the waveform wasn't as square as it might be.

[john-100]

two issues with the DB25-1205 breakout board
one is the PC817 opto-isolator used are slow
second with stepper drivers like the DM542A with opto-isolated inputs it is better not to use a BOB with opto isolated outputs

DB25-1205 BOB

DM542A Stepper driver inputs


you will see the BOB has NPN outputs with 1K pull up resistors
the only way to pass enough current through the driver input LEDs
is to connect the +step , +dir & +enable to the BOBs common +5V

John

PS

wiring diagram using common 0V that wiil not work very well with DB25-1205 breakout board 1K pull up resistors

[Toinvd]

are you sure your motor wires are wired correctly. That might cause these kind of error.
With a meter check if there is a low resistance between the two wires of each pair A+ to A- should be low, just as B+ to B-

[routalot]

Perhaps I should have added that I have a 5volt feed to the board.While I don't have the depth of technical knowledge to understand the intricacies of opto-isolators, I was reassured to know that having them reduced the chances of the magic smoke escaping.Speed wasn't really a concern for my hobby system as there are other factors which limit the rate at which I can remove material.

[automationtechinc]

I don't see any mention of a power supply for the DM542A.I have attached a file of the inside of my control box which shows the DB25-1205 at the top,the DM542A controls next down and the 36 volt power supply to the right.As mentioned earlier,I don't use Mach3 but LinuxCNC but the electrical system just sees pulses regardless of the software used.The most significant criticism I have seen regarding the DB25-1205 showed that the waveform wasn't as square as it might be.

use this wiring as a reference:

https://www.automationtechnologiesin.../ALLDriver.pdf

https://www.automationtechnologiesin...tepper-driver/