Hi
Well I was happy. Machine set up and motors tuned. Well thinks i. Let's test it
Clamp a stop, bring a dti up to it, zero move x 100 away bring it back. Still zero, great
Now to test for missing steps as in the manual ( same program as in the manual)

Set up a loop
Move x 100 move it back
Do it 5 times for a start. Will do more  loops later coz I'm new to mach 3

Curious when run the dti only makes contact at the beginning and end of the program!
Slow feed rate, look again. Yup, the x changes direction about 4-5 mm away from the stop, oh same at the other end of the gauge block
 Grrrr it shouldn't do that.
Hmmmm how much?  lets find out Do it in single step mode
Uh???  Very STRANGE. DTI NOW REGISTERS ON THE  STOP ON ALL REPEATS

this is all strange I went through the configs taking off anything which could affect it and run the program again and again to no avail

Any ideas, or am I doing somthing daft? 

Sounds like you're in CV mode. Even with just one axis in motion I think Mach3 will blend consecutive moves. Put a G61 (CV off/exact stop mode) at the beginning of your test code and see what happens.

Yup you were right!
Went oout on me bike for a good spin and had the thought that it must be somtbing like taht

Thanks

Why don't they put  the G61 in the program in the manual?
Stoopid I wasted yet more time on this, still its all a learning curve!