Now it does work, so it must have been pilot error of some sort, although I feel sure I'm not doing anything differently today.
I have made a point of closing and reopening mach after each change to macropump file, but then I'm sure I did that yesterday as well. Maybe not...
Using the MDI line to provide a testable axis movement, it stops the axis (not very abruptly, but well enough for this application,) and gives me a status line that says 'MDI line paused.. hit CycleStart to continue'. As I don't want it to continue with the paused move, but instead go to the next line of code, I was thinking of adding 'DoOEMButton(1021)' twice after the 'Else' statement.
This seems a clumsy way to achieve this, is there a more 'normal' way to get it to execute the next line after stopping the axis's movement?