Siemens SINUMERIK 840D sl Function Manual page 821

precisely to indexing position 2. The next indexing position (in this case indexing position 3) is
not approached with the "Traverse to next position" command until the axis is located exactly
at (exact stop fine) or above the indexing position.
The nearest indexing position in the current direction of motion is always approached! Under
certain circumstances, it is therefore necessary to issue the "traverse to next position"
command twice to move from the currently displayed indexing position to the next indexing
position number (e.g. from 2 to 3).
System variables
The display depends on the setting in machine data:
MD10940 $MN_INDEX_AX_MODE (settings for indexing position)
Bit
0
The following graphics will illustrate the difference between bit 0 = 0 and bit 0 = 1:
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$AA_PROG_INDEX_AX_POS_NO[<Achse>] programmed indexing position
Description:
0: not an indexing axis, therefore no indexing position available – or the indexing axis is
presently not traversing to an indexing position
> 0: Number of programmed indexing position
$AA_ACT_INDEX_AX_POS_NO[<Achse>] actual indexing position
Description:
0: not an indexing axis, therefore no indexing position available.
> 0: Number of the last indexing position reached or passed
Extended Functions
Function Manual, 10/2015, 6FC5397-1BP40-5BA3
Value Meaning
0 The indexing position changes when the indexing position is reached ("exact stop fine"
window) and remains unchanged until the next indexing position is reached. The in‐
dexing area thus begins at one indexing position and ends in front of the next indexing
position.
1 The indexing position changes when reaching half the indexing position.
A quasi-symmetrical indexing range is thus applied around the indexing position (sym‐
metrical only for linear axes with equidistant indexing or modulo rotary axes on which
the indexing area is an integer multiple of the modulo range (MD30330 $MA_MODU‐
LO_RANGE), otherwise proportional to the distances between the indexing positions).
On modulo rotary axes, the area between the last indexing position and the first index‐
ing position is divided proportionally based on the lengths of the first indexing area and
the last indexing area.
T1: Indexing axes
16.3 Commissioning
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