HEIDENHAIN TNC 320 User Manual page 277

Please note while programming:
With very small tolerance values the machine cannot cut
the contour without jerking. These jerking movements are
not caused by poor processing power in the TNC, but by
the fact that, in order to machine the contour element
transitions very exactly, the TNC might have to drastically
reduce the speed.
Cycle 32 is DEF active which means that it becomes
effective as soon as it is defined in the part program.
The TNC resets Cycle 32 if you
Redefine it and confirm the dialog question for the
tolerance value with NO ENT.
Select a new program with the PGM MGT key.
After you have reset Cycle 32, the TNC reactivates the
tolerance that was predefined by machine parameter.
In a program with millimeters set as unit of measure, the
TNC interprets the entered tolerance value in millimeters.
In an inch program it interprets it as inches.
If you load a program with Cycle 32 that contains only the
cycle parameter Tolerance value T, the control inserts the
two remaining parameters with the value 0 if required.
As the tolerance value increases, the diameter of circular
movements usually decreases. If the HSC filter is active
on your machine (ask your machine tool builder, if
necessary), the circle can also become larger.
If Cycle 32 is active, the TNC shows the parameters
defined for Cycle 32 on the CYC tab of the additional status
display.
The TNC does not evaluate the HSC-MODE and TA cycle
parameters. Although they can be entered for
compatibility reasons, they are without effect.
HEIDENHAIN TNC 320 277