OK, I seem to have a rudimentary handle on this but I just wrote another tap and on line 540 (the 540 in the centre) it occasionally sends the router to X+683 instead of the coded X-683. Any ideas on what to do to stop this please ?
N0000 (Combined L & R Fig12 Targets with offset shift)
N0010 (Post processor: Mach2.post)
N0020 (Date: 20/04/2007)
N0030 G21 (Units: Metric)
N0040 G40 G90
N0050 F1
N0060 (Part: ~$Fig12RHmod001)
N0070 (Process: Outside offset 0, Mill/Router, 5 mm diameter, 5 mm Deep)
N0090 M06 T1 (Mill/Router, 5 mm diameter)
N0120 M03 S500
N0125 G00 Z40
N0130 X-325.5000 Y231.0000
N0150 G00 Z0.0000
N0160 Z-15.0000
N0170 G01 X122.0979 F1500
N0180 G02 X125.9975 Y229.9065 I0.0000 J-7.5000
N0190 G01 X329.3996 Y106.0965
N0200 G02 X333.0000 Y99.6900 I-3.8996 J-6.4065
N0210 G01 Y-99.6900
N0220 G02 X329.3996 Y-106.0965 I-7.5000 J0.0000
N0230 G01 X125.9975 Y-229.9065
N0240 G02 X122.0979 Y-231.0000 I-3.8996 J6.4065
N0250 G01 X-325.5000 Y-231.0000
N0260 G02 X-333.0000 Y-223.5000 I0.0000 J7.5000
N0265 G01 Y-216 Z0.0
N0270 G01 Y-137.0000
N0280 G02 X-325.5000 Y-129.5000 I7.5000 J0.0000
N0290 G01 X-267.5000
N0300 G03 X-267.5000 Y-124.5000 I0.0000 J2.5000
N0310 G01 X-325.5000
N0320 G02 X-333.0000 Y-117.0000 I0.0000 J7.5000
N0330 G01 Y-73.5000
N0340 G02 X-325.5000 Y-66.0000 I7.5000 J0.0000
N0350 G01 X-285.5000
N0360 G03 X-285.5000 Y-61.0000 I0.0000 J2.5000
N0370 G01 X-325.5000
N0380 G02 X-333.0000 Y-53.5000 I0.0000 J7.5000
N0390 G01 Y53.5000
N0400 G02 X-325.5000 Y61.0000 I7.5000 J0.0000
N0410 G01 X-285.5000
N0420 G03 X-285.5000 Y66.0000 I0.0000 J2.5000
N0430 G01 X-325.5000
N0440 G02 X-333.0000 Y73.5000 I0.0000 J7.5000
N0450 G01 Y117.0000
N0460 G02 X-325.5000 Y124.5000 I7.5000 J0.0000
N0470 G01 X-267.5000
N0480 G03 X-267.5000 Y129.5000 I0.0000 J2.5000
N0490 G01 X-325.5000
N0500 G02 X-333.0000 Y137.0000 I0.0000 J7.5000
N0550 G01 Y216
N0510 G01 Y223.5000 Z-15.00
N0520 G02 X-325.5000 Y231.0000 I7.5000 J0.0000
N0530 G00 X-325.5 Y231.0 Z0.0
N0540 G52 X-683 Y0.00 (Set Temp Offset)
N0000 (Filename: ~$Fig12LHmod008.tap)
N0010 (Post processor: Mach2.post)
N0020 (Date: 19/04/2007)
N0030 G21 (Units: Metric)
N0040 G40 G90
N0050 F1
N0070 (Process: Outside offset 0, Mill/Router, 5 mm diameter, 5 mm Deep)
N0090 M06 T1 (Mill/Router, 5 mm diameter)
N0130 X333.0000 Y223.5000
N0150 G01 Z-10.00 F1500
N0160 Z-15.0000
N0170 G03 X325.5000 Y231.0000 I-7.5000 J0.0000
N0180 G01 X-122.0979
N0190 G03 X-125.9975 Y229.9065 I0.0000 J-7.5000
N0200 G01 X-329.3996 Y106.0965
N0210 G03 X-333.0000 Y99.6900 I3.8996 J-6.4065
N0220 G01 Y-99.6900
N0230 G03 X-329.3996 Y-106.0965 I7.5000 J0.0000
N0240 G01 X-125.9975 Y-229.9065
N0250 G03 X-122.0979 Y-231.0000 I3.8996 J6.4065
N0260 G01 X325.5000 Y-231.0000
N0270 G03 X333.0000 Y-223.5000 I0.0000 J7.5000
N0275 G01 Y-216 Z0.0
N0280 G01 Y-137.0000 F1500
N0290 G03 X325.5000 Y-129.5000 I-7.5000 J0.0000 F1000
N0300 G01 X267.5000
N0310 G02 X267.5000 Y-124.5000 I0.0000 J2.5000
N0320 G01 X325.5000
N0330 G03 X333.0000 Y-117.0000 I0.0000 J7.5000
N0340 G01 Y-73.5000
N0350 G03 X325.5000 Y-66.0000 I-7.5000 J0.0000
N0360 G01 X285.5000
N0370 G02 X285.5000 Y-61.0000 I0.0000 J2.5000
N0380 G01 X325.5000
N0390 G03 X333.0000 Y-53.5000 I0.0000 J7.5000
N0400 G01 Y53.5000
N0410 G03 X325.5000 Y61.0000 I-7.5000 J0.0000
N0420 G01 X285.5000
N0430 G02 X285.5000 Y66.0000 I0.0000 J2.5000
N0440 G01 X325.5000
N0450 G03 X333.0000 Y73.5000 I0.0000 J7.5000
N0460 G01 Y117.0000
N0470 G03 X325.5000 Y124.5000 I-7.5000 J0.0000
N0480 G01 X267.5000
N0490 G02 X267.5000 Y129.5000 I0.0000 J2.5000
N0500 G01 X325.5000
N0510 G03 X333.0000 Y137.0000 I0.0000 J7.5000
N0515 G01 Y216
N0520 G01 Y225.5000 Z-15
N0530 G00 Z25.0000
N0535 M05
G52 X683 Y0.0 (Cancel Offset Shift)
N0580 Y460
N0590 X-325.5
M30