Hi,

sounds like your accel is to high, start it low, very low and see if that fixes the problem. Then you can experiment to find

the useful maximum for your machine.

You can use the auto-cal function, I don't because I built my machine and I KNOW the parameters and can calculate the

steps per EXACTLY. The auto-cal function is for people who don't know their machine and can't be bothered to find out

and/or get confused over basic arithmetic. You decide which camp your in.

Work your axis backwards and forwards using MDI, going a useful distance each time. Set x=0 then go to x=4in and the back to x=0.

G0 X0

G0 X4

G0 X0

It should go back to the exact starting point. If it doesn't no setting or autocalibration is going to do you any good.

The numbers on the motor tuning screen are:

Step per unit, as discussed above should be 8128

Velocity in/min, recommended less than 98in/min, say 30in/min for a conservative starting point.

Acceleration in/sec/sec, recommended less than 9.8 in/sec/sec, say 3in/sec/sec for a conservative starting point.

G's, this is a display only and tells you the 'G force' corresponding to your acceleration setting above. For hobby machines

0.01 to 0.1 are common, high speed production machines can go upwards of 10.

The next two parameters are the pulse length presented to the motor drive by Mach3. My drivers are good quality Japanese ones

and the specs say 1.25us is enuf. If you have crappy ones 5-10 us might be better. If the pulse is to short the driver might miss it

altogether. Note that when you make alterations on the tuning page you have to 'save before exit' or the changes will not be implemented.

The trick to getting this stuff to work is not to change everything at once, change one item and establish what effect it has. If you can

understand each effect then you are well placed to find the right balance of parameters/settings.

Craig