Position tolerance is the most commonly used symbol
in GD&T geometric tolerancing,
The True Position is the exact coordinate, or location allowable
in the defined dimensions of a feature. Position tolerance
can also be used together with MMC
Maximum material condition and LMC
Least material condition.
Position tolerance reference to a datum of size.
Positioning tolerance of diameter 0.2 reference to datum A,B
and C. The center location of the diameter 20 hole can fall
within the range of diameter 0.2 in both X and Y axis.
tolerance use with MMC, Maximum Material Condition.
hole size is at MMC Maximum Material Condition, Diameter 19.99.
The positioning tolerance is called for 0.2. When the hole
size is at 20.01, LMC Least Material Condition, the positioning
tolerance will be 0.2+0.02=0.22. Meaning the center location
of the hole at LMC can fall within the range of diameter 0.22.