The internet is a wonderful thing and I have learned more from forums like this one that I ever did at school.
However one of the small frustrations is that there is always misinformation mixed in with the good.
It is my strong desire to not add misinformation, particularly to this most informative thread of Tweakie's.
So I need to clear up what I have said about outputs used by the engraving plugin.
What testing has told me is that the plugin uses Digital Trigger only. The really odd thing is that it uses Digital Trigger even when it is disabled.
My previous belief that it could also use Output1 was because it worked when Digital Trigger was disabled and Output1 was enabled.
But it was not using the enabled Output1, it was in fact using the disabled Digital Trigger.
If you look at the pic of Ports and Pins, you will see that I had both outputs set to port1 pin9.
Not a good idea, but I had it set thus, as I was swapping back and forth to try and see what was going on, in the mistaken belief that disabling one and enabling the other was sufficient to change the output. WRONG.
Don't know what to think of that. A bug or my lack of understanding as to how Mach works.
Now the important thing after all this, is that I was wrong. It is NOT sufficient to just disable an output in this case.
As Tweakie said, Digital Trigger is the correct output to set up for the engraving plugin.
Sorry for my misleading posts and I hope this clears it up.
Greolt