Siemens SINUMERIK 840Di Function Manual page 587

A REPOSMODE specified by the PLC is acknowledged by the NCK with:
DB21, ... DBX319.1-319.3 (Repos Path Mode Ackn0 to 2)
and
DB31, ... DBX10.0 (Repos Delay)
with:
DB31, ... DBX70.2 (Repos Delay Ackn)
as follows:
A part program is stopped at N20 (→ time (2) in figure). The NCK stops according to the
braking ramp. After the PLC has specified the REPOSPATHMODE, the NCK accepts the
REPOSPATHMODE with the 0/1 edge of REPOSMODEEDGE at → Time (3). Repos Path
Mode Ackn remains set until the ASUB is initiated (→ Time (4)). The REPOS command is
started in the ASUB (→ Time (5)). The ASUB RESET block is activated again (→ Time (6)):
Fig. 2-6
NCK sets acknowledgement again
Phase with REPOSPATHMODE still active (residual block of the program stopped at → Time
(2) is not yet completely executed).
As soon as the REPOS repositioning motion of the ASUB is executed, the NCK sets the
"Repos Path Mode Ackn" again (→ Time (5)). If no REPOSPATHMODE has been
preselected via a VDI signal, the programmed REPOS mode is displayed.
"Repos Path Mode Ackn" is canceled when the residual block is activated (→ Time (6)).
The part program block N30 following the block at → Time (2) is resumed.
Mode Group, Channel, Program Operation, Reset Response (K1)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
REPOS sequence in part program with timed acknowledgement signals from NCK
Detailed Description
2.6 Block search Type 5 SERUPRO
2-51