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

[Davek0974]

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.

[Davek0974]

CandCNC advised me to up the pulse width to 5us and that seems to have sorted it out, all drives now running the same way.

[JAZZCNC]

CandCNC advised me to up the pulse width to 5us and that seems to have sorted it out, all drives now running the same way.

So you were just on the wrong side of the pulse edge then. Could only really be this or the BOB inverting signals really.! Changing the pulse width doesn't always work thou unfortunately so you've been fortunate.!

[Davek0974]

Yes its an oddity i think,

A Mach guru has just pointed out that the BOB has opto isolated outputs and the drives have opto isolated inputs so i am driving an opto with an opto, he seemed to feel that was not a good idea generally.

[JAZZCNC]

Yes its an oddity i think,

A Mach guru has just pointed out that the BOB has opto isolated outputs and the drives have opto isolated inputs so i am driving an opto with an opto, he seemed to feel that was not a good idea generally.

Nah not at all it's common as muck with Just about every BOB worth it's salt having opto's has will any decent drives and there'll be few machines that don't run with both.!

Unfortuantlly it's more a sign of poor drive or BOB with slow opto's.!!

[cropwell]

If every bit and bob and driver has opto isolation why not cut out the middle man and have a fibre optic connection ? I'll bet there are some machines with bespoke electronics that do it.

[Davek0974]

If every bit and bob and driver has opto isolation why not cut out the middle man and have a fibre optic connection ? I'll bet there are some machines with bespoke electronics that do it.

Probably purely a cost issue, this stuff is not really found on the high-end machines, I have no doubt those ones would have fibre where needed.

:)