NPTH Annular Ring (Drill)

Reports the shortest distance between drill and laminate for NPTHs embedded in copper if closer than pp_d2c.

Internal ERF Name	<Area>:npth_ar
Measurement Shape Measurement Value Measurement ID	Segment Ring NPTH; Feature (or r0)
Layers Displayed	Signal layer Drill layer that pierces it
Graphic
Purpose
Function	Reports the shortest distance between drill and laminate for NPTHs embedded in copper if closer than pp_d2c. Measurements are segments representing distance between the NPTH and nearest laminate.
ERF Parameters	pp_layer pp_d2c
ERF Variables	limited_npth_check
Limitations	If there is any copper in the NPTH, then a zero annular ring measurement is reported. This may be considered by some to be a false alarm. Where NPTH AR is composed of more than one feature (such as in drawn surfaces), the measurement entity will be r0.