Siemens SINUMERIK 840D sl Function Manual page 428

Commissioning
9.6 Replacing a motor or encoder
The user agreement is set for the axis, i.e. the axis has had the status "safely ref-
erenced" at least once – the actual position value of the NC and the SI actual val-
ues (axis/drive) have been appropriately calibrated.
"Safe limit positions" or "Safe cams" have been able to be used.
A motor or motor encoder has to be replaced under these conditions.
Replacing a motor with absolute value encoder
In order to set–up the encoder, the offset between the machine zero and the zero
of the absolute encoder was determined.
The calibrated state is identified by the control using
MD 34210: ENC_REFP_STATE = 2.
The important factor when replacing a motor (also without Safety Integrated) is that
a defined position reference can be established with respect to the mechanical
parts of the machine. For example, by mounting and removing the motor at a de-
fined mechanical position or appropriately re–calibrating the system after the motor
has been replaced.
After the old motor has been removed and the new motor installed, another actual
position value is read by the new absolute value encoder (there is no longer a de-
fined reference to the correctly calibrated actual position value).
Therefore the following error profile appears when the control boots:
Alarm 27001
values: NCK x, drive y.
The comparison between the saved stop position and the actual position indicates
a larger deviation than that specified in MD 36944: $MA_SAFE_REFP_POS_TOL
or parameter p9544: "SI motion, actual value comparison tolerance (referencing)"
The alarm results in a STOP B followed by a STOP A (safe pulse cancellation) for
the axis involved.
The user agreement is also cancelled. This means that the axis loses the status
"safely referenced" in connection with the Alarms 27000/C01797 axis <name of the
axis> not safely referenced.
The actual position value supplied by the new motor encoder has no reference to
the mechanical system. This means that the absolute value encoder must be re–
aligned and set–up at this point.
Note
A safety acceptance report is generally not required after a motor has been
replaced.
9-428
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 05.2008 Edition
Axis <name of the axis> fault in a monitoring channel, Code 1003,
© Siemens AG 2008 All Rights Reserved
05.08