Tandem Axis on 2.8

I was running my 3 axis router linuxcnc 2.7 on Debian Wheezy with 1 stepper motor per axis.
I've replaced it with a new router which has a tandem X-axis - but kept the same control system (using Mesa 5i25 + 7i76 card combo) adding one more stepper drive. I've upgraded the PC to Debian Stretch & linuxcnc 2.8 to use the gantry squaring feature.

I used Pncconf to generate the HAL & INI files. The Z & Y axes home and jog properly but I can't get the tandem X to move or home. When I click "home all" in the Axis GUI the DRO for X changes as if the axis was moving but there is no actual movement.

I've attached my HAL & INI files & would be grateful if anyone could point out anything I have overlooked or done wrong. These files are as generated by Pncconf - except I deleted "kinstype=both" from the following line:

Thanks for your help,
Nathan

Many thanks Tommy - that worked!

I changed step space and step length to 5000 - the drives are DM542T.

Strangely the old shorter settings for step space & length worked when I tried a dummy configuration with one motor per axis (XYZA) - but not when two motors were in tandem.

So I can confirm that the PnCConf generated HAL & INI files worked perfectly without any further editing required.

Nathan