MACH3, Dell 2g machine running Windows 7, Parallel breakout and a generic 6040 router. I did have this working when I set it all up after purchasing it some 4 or 5 years ago but it has sat unloved since then. I cut a new instrument panel for my sailplane with it but now want to re-jig things so broke out the system and have been getting everything running again.

The controller breakout was replaced by a NOVUSUN ethernet unit so config was lost, I have now swapped back to the parallel HK breakout board.

JOG works. Lovely and smooth.
Generate Frequency works ... nice and smooth.

But trying to set the steps or run GCode results in stalled and noisy motors.

Break out the oscilloscope after much fiddling ....

In Jog and frequency modes the DIR signal works as expected, only reversing polarity when a change of motor direction is required.

In axis setup and GCode run the direction signal is changing on each pulse step with the result that the motors effectively stand still!

Most bizarre.

Disconnecting the DIR signal allows the motors to step ax expected but obviously with no direction control, defaulting to the drivers default direction.

Any help? ( Ireally want to go and fly this weekend with my new little electrical sub-panel in place! )

Have you got the DIR polarity wrong?  Sounds like the dir signal state may be changing on the edge of the pulse signal.

I don't think so. It works for jog just fine.

In Jog the signal only changes when a different direction is commanded.

In normal moves the direction signal toggles to coincide with each step pulse.

Quite, but if the edges of dir and step are synchronous the driver may not respond properly.  Very easy to try, just a tick box in config.

I'll go try that. Any clue on the config box to tick?

And any idea why it does it for moves but not for jog and frequency generate?

See Figure 5.4 on page 5-3 of the manual Rev 1.84-A2.  Look at the Dir LowActive column.

For jog the dir level is constant unless direction changes.  What do you mean by frequency generation?

servo frequency generator. 2000 hz reverse every 2 seconds ....... X axis cycles back and forth nicely.

In G move DIR should stay the same if direction change is not required. Mine seems to be toggling at every step.

Just try changing the polarity as suggested.  Can't hurt, may solve your problem.

thanks. Changed dir and step polarities individually and both. All the Dir does is change direction effective when jogging but no change when moving unde program ( well the motor tones change quite a bit but thats it)

This is very similar to a very old issue I found ( 2008? ) on another forum where accelerations and speeds were suspect. Played with all of those to little effect!

Baffled as to why it works in Jog but not under control of GCODE