Siemens SIMODRIVE POSMO A User Manual page 157

5 Description of the Functions
5.5 SIMODRIVE POSMO A functions
Limitations when
referencing
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5-156
The following limitations apply when referencing:
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The positioning motor supplies the following zero marks:
– 75 W motor ––> 4 zero marks per motor revolution
– 300 W motor ––> 1 zero mark per motor revolution
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The position of the zero mark, which was last recognized, is over-
written with the value in P5 (reference point coordinate) by setting
STW.11 (start referencing/stop referencing).
The actual position to be written is corrected by the distance which
was traveled since the last zero mark.
Prerequisite:
The axis must be at a standstill and be in closed–loop control.
If the axis is moving, then the value is not accepted and an warning
is output.
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If the motor was not moved after being powered up, i.e. a zero mark
has still not been passed, and therefore there is no valid position for
a zero mark, then referencing is rejected and a warning output.
The "referenced" status is lost.
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Generally, the following is valid:
ZSW.11 (reference point set/no reference point set) is used to dis-
play whether an axis is referenced.
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Resetting the status "reference point set" (from SW 1.4)
For a stationary axis that has been referenced, the "no reference
point set" state is re–established by writing a 0 into P98.
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The following applies for a non–referenced axis:
– No blocks with absolute position data are executed.
– The axis zero of the axis is the position after the drive has been
powered up.
Warning
For non–referenced axes, the software limit switches are not
monitored.
Suitable measures must be implemented in the system (e.g. hardware
limit switches) in order to avoid injury to personnel and damage to the
machine.
SIMODRIVE POSMO A User Manual (POS1) – 08/2013 Edition
E Siemens AG 2013 All Rights Reserved
04.01 02.99