Motor Max Speed problem

[Hood]

What is the pitch of screws and have you any gearing between motor and screw?
Reason I am asking is I am just wondering what RPM your steppers will actually be running when you are attempting 500IPM.
Hood

[kb18951452]

~1275 steps per inch. I don't know all the gearing details, but i do remember that the steps per is ~1275 (maybe 1272.24)

[Hood]

That doesnt sound much, 200 steps per rev of motor x 10uS of drive is 2000 per rev of motor so your axis moves over 1.5 inches per motor rev?
Hood

[kb18951452]

that sounds about right.

[Hood]

So what kind of screws do you have? or is it a rack and pinion?
Hood

[kb18951452]

R&P and i don't know the pulley diameters (Only needed to know them when calculating things at the beginning.)

[HimyKabibble]

I would guess the problem may well be the Breakout board.  I suspect you're seeing the upper limit of the step pulse frequency it will pass through, and beyond that point the step pulses are "aliasing", so the frequency coming out of the BOB is lower than the frequency going in.  CNC4PC uses some strange pulse-shaping circuitry on their boards that I could see causing that kind of problem if you've got a defective chip or component on the board.  It would be instructive to try temporarily wiring up a different breakout board, or even a completely passive one, just on a single drive, and see what happens.

Regards,
Ray L.

[kb18951452]

I actually replaced the ICs on this board after i conencted 12v to the 5v terminal.....

Do you recommend a BOB? I'm familiar w/ cnc4pc, and would probably just get he updated version of this board.

[kb18951452]

So. It appears to have been the BOB. Replaced it.

We are having a diff problem now, however.

One side of the gantry seems to be running faster than the other.

I am wondering: We slaved the A to the X, and since then have adhjusted the steps per inch rate for the motors. Is there a chance that the steps per inch isnt getting properly applied to one of the motors? Maybe we need to unslave change the settings, then reslave the motors?