Siemens SINUMERIK 840D sl Function Manual page 824

T1: Indexing axes
16.4 Programming
Special features
● Modulo rotary axis as indexing axis
On modulo rotary axes, the indexing positions are divided in factors of 360° and approached
directly.
● Indexing axis is between two indexing positions
The specified position instructions have the following effect in the AUTOMATIC mode.
System variables
The number of the indexing position programmed last can be read with the following system
variables:
$AA_PROG_INDEX_AX_POS_NO
The number of the indexing position traversed last can be displayed with the following system
variables:
$AA_ACT_INDEX_AX_POS_NO
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:
824
POS[B]=CIC(1)
POS[B]=CIC(-1)
POS[B]=CIC(0)
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 half the indexing position is reached.
A quasi-symmetrical indexing area is thus applied around the indexing position (sym‐
metrical only on 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.
The next higher indexing position is approached.
The next lower indexing position is approached.
The indexing axis is not traversed.
Function Manual, 10/2015, 6FC5397-1BP40-5BA3
Extended Functions