Second CNC table build, here we go again....

**JAZZCNC** · 10-09-2015

Originally Posted by Davek0974

Any ideas why I need to run two axes reversed signal level???

If all wired same and the drive doesn't have an active edge Dip switch then probably because setup different in the drive software. Some drives will provide a Dip and most Digital drives you can access thru software.

If none of the above then could just have been set different at the factory,?

**Dragonfly** · 10-09-2015

"Active Low" means the drivers are wired with common +5V and step pulse inputs wired to the minus terminals, right?

**Davek0974** · 10-09-2015

Originally Posted by Dragonfly

"Active Low" means the drivers are wired with common +5V and step pulse inputs wired to the minus terminals, right?

Yes, all wired common +ve

**Davek0974** · 10-09-2015

Originally Posted by JAZZCNC

If all wired same and the drive doesn't have an active edge Dip switch then probably because setup different in the drive software. Some drives will provide a Dip and most Digital drives you can access thru software.

If none of the above then could just have been set different at the factory,?

But these were tested with a different BOB when i was building the table and all settings were the same????

One difference is that the test PC was underpowered and only ran at 25khz, the work PC runs at 45khz, step and dir pulse length is 2us on both PC's

**JAZZCNC** · 10-09-2015

Originally Posted by Davek0974

But these were tested with a different BOB when i was building the table and all settings were the same????

One difference is that the test PC was underpowered and only ran at 25khz, the work PC runs at 45khz, step and dir pulse length is 2us on both PC's

Don't know then. Maybe the new BOB does some filtering and signal boosting depending on the PP voltage.? If your on the edge with say 3V PP then the BOB could be boosting and inverting the signal just on that line.??? . . . .Strange beasts these CNC machines.!!!!

**Davek0974** · 10-09-2015

Hmm, interesting

Just thought of another difference, the CandCNC MP3000 DTHC uses three parallel cables - one from the pc to the controller and then one to the motor drive BOB and another to the I/O BOB, these last two are new, shorter cables.

Might be worth swapping the old long cables back in???

**Dragonfly** · 10-09-2015

Don't think cable length is the cause. Anyway I see only one BOB on the photo and presumed you use Mach3.
Actually did you test all drivers set to "active low"? As far as I understand you have Y and A coupled as master and slave. Wrong polarity might make them "rough" as they need to move in sync while the others may also need low trigger but do not show rough movement because they are single. ??Hmm.

**Davek0974** · 10-09-2015

The mp3000 has two BOB's one for motor control and one for inputs and outputs, yes i am running mach3

All drives were running active low on the test pc, Y and A are slaved in mach and each on their own output.