Good morning,
I'm a retired computer engineer and I'm using (as a beginner) Eagle 6.2.0 Light. Just as an hobbyst.
My goal is to use Eagle in order to plot the circuit on a HPGL plotter.
I've made a basic test, directly on a board panel (no schema).
1 - Define first a dimension 3 inches X 2 inches.
2 - Create two VIAS at coordinates 1,1 and 2,1
3 - Draw a wire between the two Vias.
Then with Cam processor I output a HPGL file and an Excellon one (no offset required, pen set to 0.35 mm for HPGL)
HPGL
IN; IP 0,0,100,100; SC 0,100,0,100;
SP 2;
PA 1031,1031;
PD;
PA 2047,1031;
PU;
SP 6;
PA 994,1068;
PD;
PA 987,1075;
PA 1075,1075;
PA 1075,987;
PA 987,987;
PA 987,1075;
PA 997,1068;
PA 997,994;
PA 1007,994;
PA 1007,1068;
PA 1016,1068;
PA 1016,994;
PA 1026,994;
PA 1026,1068;
PA 1036,1068;
PA 1036,994;
PA 1046,994;
PA 1046,1068;
PA 1055,1068;
PA 1055,994;
PA 1065,994;
PA 1065,1068;
PU;
PA 2010,1068;
PD;
PA 2003,1075;
PA 2091,1075;
PA 2091,987;
PA 2003,987;
PA 2003,1075;
PA 2013,1068;
PA 2013,994;
PA 2023,994;
PA 2023,1068;
PA 2032,1068;
PA 2032,994;
PA 2042,994;
PA 2042,1068;
PA 2052,1068;
PA 2052,994;
PA 2062,994;
PA 2062,1068;
PA 2071,1068;
PA 2071,994;
PA 2081,994;
PA 2081,1068;
PU; SP 0; PA 0,0;
Excellon
%
M48
M72
T01C0.0236
%
T01
X10150Y10150
X20150Y10150
M30
Now my questions :
1 / I was expecting 2 holes at coordinates
X10000Y10000
X20000Y10000
Why is there an offset of (15,15) mil in the output file ?
2 / I was expecting a drawing (HPGL) with vias centerd on the requested coordinates (1,1 and 2,1)
Just consideringf the wire, the output is
SP 2;
PA 1031,1031;
PD;
PA 2047,1031;
PU;
where I was expecting
SP 2;
PA 1000,1000;
PD;
PA 2000,1000;
PU;
Here is seems that there is and offset of (31,31) mil and a distance of 2016 mil... for one inch 
I certainly made someting wrong somewhere (I clearly don't think that's an Eagle bug). But what and where ?
I would like sone consitency in the coordinates output and in my brain 
Does somebody have answers ?
Regards
Marc
