5v and db25

[FPD]

First build using acorn and I am just curious about something. In the manual on page 53, the KL-5080H drivers is not connected to the 5v from power supply, but rather make use of the Com(-) ports on db25. What is the reason for not using the 5v from power supply although the schematics show it. I bench tested my driver(completely different driver) according to the schematics, and everything works. However I was just curious why some use the com on db25 and not 5v+

[ShawnM]

I'm confused as to what you are asking. What manual are you referring to? Are you following diagram S14973 for the KL-5080H? You wire 5v from your power supply to the PUL+ and DIR+ on the drives and then you wire the PUL- and DIR- to the respective STEP and DIRECTION pins on the DB25. They are not wired to the COM pins.

[FPD]

In the Acorn controller Install manual. They wire the pul - etc to port 18 and 19, which is Com on db board and no 5v from power supply. I tried attaching a photo, but the forum logs me out every time.

[Nigelo]

The DB25 is supplied with 5vdc from the board itself i.e. not a separate supply. Centroid's Installation manual shows a photo on page 54 with connections as follows:

- Red wire from DB25 Pin 2 to drive Pul+
- Black wire from DB25 Pin 3 to drive Pul -
- Blue wire from DB25 Pin 18 to drive Dir+
- Yellow wire from DB25 Pin 19 to drive Dir-

However, as Shawn has correctly pointed out, always follow the Schematic for your specific drive (S14973) bearing in mind that photo in the installation manual is just a generic example that happens to be your drive.

IIRC there are 2 ways of connecting drives (possibly Sinking or Sourcing but I'm not sure of the exact terminology) which may explain why the Schematic differs from the photo. In both cases, you will note that PUL+ / DIR+ are supplied with +5vdc and PUL- / DIR- with COM

[ShawnM]

In the Acorn controller Install manual. They wire the pul - etc to port 18 and 19, which is Com on db board and no 5v from power supply. I tried attaching a photo, but the forum logs me out every time.

As Nigel pointed out the install manual is for reference only and ironically shows a pic of your drive as an example. If you go to the Acorn Schematic page and type in your drive model number at the top in the "search" box you'll be shown Rev4 of the wiring schematic for your drive, S14973. Follow this schematic, it's just works.

https://www.centroidcnc.com/dealersuppo ... 973.r4.pdf

[FPD]

Thank you Nigel and Shawn. I have completely different drivers and wire it according its schematics. I was just curious why its wired differently than the schematics on this specific driver.

[ShawnM]

Thank you Nigel and Shawn. I have completely different drivers and wire it according its schematics. I was just curious why its wired differently than the schematics on this specific driver.

I cannot answer that question but Centroid spends countless hours creating schematics for various drivers and they are all listed on the schematic page. Those are the diagrams that one should follow as they have been tested to work.