Siemens SINUMERIK 840D sl Function Manual page 288

Data Description
8.1 Machine data for SINUMERIK 840D sl
36942
MD number
Default value: 0.1
Change becomes effective after: POWER ON
Data type: DOUBLE
Significance:
Special cases, errors,...
36944
MD number
Default value: 0.01
Change becomes effective after: POWER ON
Data type: DOUBLE
Significance:
Special cases, errors,...
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SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 05.2008 Edition
$MA_SAFE_POS_TOL
Tolerance, actual value comparison (crosswise)
Min. input limit: 0.001
Protection level: 7/2
Due to the fact that encoders are not mounted at identical locations and the effect of back-
lash, torsion, leadscrew errors etc. the actual positions sensed simultaneously by the NCK
and drive may differ from one another.
The tolerance bandwidth for the crosswise comparison of the actual positions in the two
monitoring channels is specified in this machine data.
S "Finger protection" (approx. 10 mm) is the primary consideration when setting this toler-
ance value.
S Stop response STOP F is activated when the tolerance bandwidth is violated.
$MA_SAFE_REFP_POS_T OL
Tolerance, actual value comparison (referencing)
Min. input limit: 0
Protection level: 7/2
This machine data specifies the tolerance for checking the actual values after referencing
(for incremental encoders) or when powering–up (for absolute encoders).
An absolute actual axis position is determined by referencing.
A second absolute actual position is calculated from the last stop position that was saved
prior to the control being powered–down and the distance traversed since power–on. The
control system checks the actual values after referencing on the basis of the two actual
positions, the traversed distance and this machine data.
The following factors must be taken into consideration when calculating tolerance values:
Backlash, leadscrew errors, compensation (max. compensation values for SSFK, sag and
temperature compensation), temperature errors, torsion (2–encoder system), gearbox play
for control gears, coarser resolution (2–encoder system), oscillating distance/range for
control gears.
If these two absolute actual positions deviate from one another by more than the value set
in this data – with a valid user agreement – then Alarm 27001 is output with Fault code
1003 and a new user agreement is required for referencing.
Max. input limit: 360
Unit: mm, degrees
Max. input limit: 36
Unit: mm, degrees
© Siemens AG 2008 All Rights Reserved
05.08