Siemens SINUMERIK 840C - Manual (Page 860)

01.99 12 Functional Descriptions
12.11.2 ENDAT absolute encoder (SW 5.2 and higher)
Function extension of the symmetrical traversing range for rotary axes (as from SW 6)
General
In the case of rotary axes with EnDat absolute encoders and up to SW 5, a position between 0
and 360 degrees or between 0 and 16 revolutions was calculated (depending on MD 1808*,
bit 6). Once switched off at an axis position of -45 degrees, e.g. a position of 315 degrees was
calculated after the next POWER ON.
Bit 0 in MD 1804* must be set to 1 in order to achieve a symmetrical traversing range around
the zero position for finitely turning rotary axes. In this case, no modulo offset is implemented
between -180 degrees and +180 degrees (if MD 1808*, bit 6=1) or between -8 to +8 rota-
tions (if MD 1808*, bit 6=0).
Examples for incorrect overflow:
MD 1808*, bit 6 MD 1804*, bit 0
Position before
POWER OFF
Position after
POWER OFF
1 0 -45 degrees 315 degrees
1 1 -45 degrees -45 degrees
1 0 315 degrees 315 degrees
1 1 315 degrees -45 degrees
1 1 2700 degrees (=7.5 rev) 180 degrees
0 1 2700 degrees (=7.5 rev) 2700 degrees
0 0 -45 degrees 5355 degrees
0 1 -45 degrees -45 degrees
0 0 3060 degrees (=8.5 rev) 3060 degrees (=8.5 rev)
0 1 3060 degrees (=8.5 rev) -2700 degrees (=7.5 rev)
The maximum traversing range for rotary axes remains at 16 rotations above which a modulo
offset is implemented.
The symmetrical traversing range is not available in conjunction with the area
expansion for the ENDAT absolute encoder (MD 1808*, bit 7=1).
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50 12–85
SINUMERIK 840C (IA)