Siemens SINUMERIK 840C Installation Instructions Manual page 863

12 Functional Descriptions
12.11.2 ENDAT absolute encoder (SW 5.2 and higher)
Example:
Position controller resolution =
Displayed actual position =
Positive travel direction
Reference point approach is not possible!
1st step
2nd step
3rd step
4th step
Ascertaining the offset without the reference point encoder
•
There is no reference point cam or BERO present.
•
NC MD 1808* bit 0: axis with absolute encoder is set (absolute encoder present).
The machine is traversed to the position that the machine manufacturer regards as the
reference point manually in "JOG" or "Incremental" mode.
Calculation of the absolute value encoder:
Where:
• Machine system = required absolute position = reference point value
• Absolute encoder value =
The calculated absolute offset must be entered in MD 396* and be made valid by setting MD
1808*, bit 3. After the next control start-up, the displayed actual position, the machine system
actual position and the status signal "Reference point reached" are set.
12–88
More user manuals on
0.5 10
140.0000
Enter 40.0000 mm in NC MD 396*, absolute offset, and set NC MD 1808*, bits
1 and 3.
After POWER ON, an actual position of 0.0001 is displayed.
Reset NC-MD 1808*, bit 3, absolute offset valid.
Execute reference point approach.
Machine system = absolute encoder value + absolute offset
or
Absolute offset = machine system - absolute encoder value
displayed absolute position (actual value) with
"Absolute offset invalid"
For set-up without reference point encoder,
the customer must take care of the overflow handling.
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SINUMERIK 840C (IA)