Siemens SINUMERIK 840D sl Function Manual page 1195

2.12.20 FC 16: PART_AX positioning of indexing axes
Description of Functions
(Do not use for new applications, function is integrated in FC 18 in SW 3.6 and higher.)
FC PART_AX can be used to traverse NC axes defined via machine data as "indexing axes",
also from the PLC.
References:
/FB2/Function Manual Expanded Functions; Indexing Axes (T1)
In order to traverse the indexing axes via the PLC, the traversing check must be activated for
the PLC. This can be achieved, for example, by calling FC "PART_AX" with activation of the
"Start" parameter. The FC "PART_AX" then requests checking of the axes from the NC. The
NC feeds back the status of this axis in byte 68 in the associated axis interface DB 31, ... see
lists/ (Book 2), Interface signals power line.
Upon completion ("InPos" is True, "Start" changes to zero), the axis/spindle check function is
switched to a neutral status by FC PART_AX. Alternatively, the PLC user program can also
request the check for the PLC prior to calling FC "PART_AX".
By calling this function several times in succession, a better response reaction by the
spindle/axis can be obtained as the changeover process in the FC can be omitted.
Activation through the PLC user program is executed in the corresponding axis interface in
byte 8.
After return of the check, the axis can again be programmed by the NC program.
Note
After the FC has been called, ACCU1 contains an error statement by the NCK (but not if the
output parameters are assigned to a data block). This is generally the value 0 (signifies: No
error has occurred). See table for the interpretation of other numerical values for error codes
in FC 15.
FC 16 must be called cyclically until the "Active" signal produces an edge transition from 1 to
0. Only when the "Active" signal has a 0 state can the axis concerned be restarted (the next
start must be delayed by at least one PLC cycle). This also applies when the assignment in
data byte 8 has changed.
The function cannot be aborted by means of parameter "Start", but only by means of the
axial interface signals (e.g., delete distancetogo).
The axial interface also returns status signals of the axis that may need to be evaluated
(e.g., exact stop, traverse command).
Basic logic functions: PLC Basic program powerline (P3 pl)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
Detailed description
2.12 Block descriptions
211