Siemens SINAMICS S120 Function Manual page 276

Function modules
7.8 Closed-loop position control
● When the switchover between drive data sets involves a change in gear unit, the position
● With identical mechanical conditions and encoder data set, a DDS switchover does not
Restrictions
● Position tracking cannot be activated for an encoder data set which is used in different
● If an encoder data set is used in one DDS as a motor encoder with position tracking and
● If position tracking is reset in one drive data set, it is also reset in all other drive data sets
● An axis in an inactive drive data set may move by a maximum of half an encoder range
The following table describes what happens on switchover from one DDS to another. A DDS
switchover always starts from DDS0.
An overview of DDS switchover without position tracking load gear can be found in section
"Instructions for switching data sets" in chapter "EPOS - referencing".
Table 7- 4 DDS switchover with load gear position tracking
DDS p186 p187
(MDS) (encoder_1)
0 0 EDS0
1 0 EDS0
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tracking function starts from the beginning again, i.e. it behaves on switchover as if a
POWER ON had occurred.
affect the status of the encoder adjustment or reference point.
drive data sets as encoder1 for different gears. If an attempt is still made to activate
position tracking, fault "F07555 (Drive encoder: Configuration position tracking" will be
displayed with fault value 03 hex.
A check is generally performed to determine whether the load gear is the same in all DDS
in which the relevant encoder data set is used.
In this case, the settings in each of the load gear parameters p2504[D], p2505[D],
p2720[D], p2721[D] and p2722[D] must be identical.
in another DDS as an external encoder, the position tracking starts from the beginning
again, i.e. it behaves in the same way as it would do after a POWER ON.
which contain the relevant encoder data set.
(see p2722: tolerance window).
p188 p189
(encoder_2) (encoder_3)
EDS1 EDS2
EDS1 EDS2
Encoder Mechanic Load gear
for al position
position condition tracking
control s
p2502 p2504/
p2505/
p2506 or
p2503
encoder_ xxx activated
1
encoder_ xxx activated
1
Function Manual, (FH1), 10/2008, 6SL3097-2AB00-0BP5
Switchover response
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Switchover during pulse
inhibit or operation has no
effect
Drive functions