Would be nice to do something about this NOP, but I think this is permanent, is that correct?
Yes both NOP and END are mandatory.
QuoteIt appears that any PL value set is relative to that JOB only (this is what you are saying)
Not relative to the job, it's worse, it's relative to the single motion instruction:
NOP
MOVL Pxx0 PL=8
MOVL Pxx1
END
In the example above, in the same JOB, the PL=8 is applied only to Pxx0. The second one has no PL specified. If you want a PL=8 then you will have:
NOP
MOVL Pxx0 PL=8
MOVL Pxx1 PL=8
END
Quotethe motion instruction appears to be executed as though I have set PL0 instead
Are you sure?
PL=0 is the highest level, it will cause a temporarily stop of the robot like the highest ACCURACY in AS.
You can set the PL "accuracy" from 1 to 8 with some S1C parameter in microns(S1CxG33...S1CxG40) but not for the PL=0.
Check in the inform manual the MOVJ instruction.