Siemens SINUMERIK 840C - Manual (Page 863)

12 Functional Descriptions 04.96
12.11.2 ENDAT absolute encoder (SW 5.2 and higher)
Example:
Position controller resolution = 0.5 10 -4 mm
Displayed actual position = 140.0000
Positive travel direction
Reference point approach is not possible!
1st step Enter 40.0000 mm in NC MD 396*, absolute offset, and set NC MD 1808*, bits
1 and 3.
2nd step After POWER ON, an actual position of 0.0001 is displayed.
3rd step Reset NC-MD 1808*, bit 3, absolute offset valid.
4th step Execute reference point approach.
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:
Machine system = absolute encoder value + absolute offset
or
Absolute offset = machine system - absolute encoder value
Where:
• Machine system = required absolute position = reference point value
• Absolute encoder value = displayed absolute position (actual value) with
”Absolute offset invalid”
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.
For set-up without reference point encoder,
the customer must take care of the overflow handling.
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SINUMERIK 840C (IA)