HEIDENHAIN ND 920 - Manual (Page 63)

63
Resetting the display to zero with an external signal
Each axis can be reset to zero with an external signal at the D-sub
connection X41 (pins 2 to 4) by means of make contact against 0 V.
Make contact against 0 V must be present for at least 100 ms.
A zero reset does not affect the current datum number.
Zero reset is not possible when a probing function is active.
Pin 3 Y
Pin 2 X
Pin 1 (0V)
Pin 4 Z
Switching Inputs and Outputs