Speed of the setting test runs, See "speed of the setting test runs, Graphics 17.1 – HEIDENHAIN TNC 640 (34059x-02) ISO programming User Manual
Page 507

Graphics
17.1
17
TNC 640 | User's Manual for DIN/ISO Programming | 5/2013
507
Speed of the Setting test runs
The most recently set speed remains active, even if
the power is interrupted, until you change it.
After you have started a program, the TNC displays the following
soft keys with which you can set the simulation speed:
Functions
Soft key
Perform the test run at the same speed at which
the program will be run (programmed feed rates
are taken into account)
Increase the test speed incrementally
Decrease the test speed incrementally
Test run at the maximum possible speed (default
setting)
You can also set the simulation speed before you start a program:
Shift the soft-key row
Select the functions for setting the simulation
speed
Select the desired function by soft key, e.g.
incrementally increasing the test speed