Siemens SINUMERIK 840C Installation Instructions Manual page 867

12 Functional Descriptions
12.11.3 Range extension with ENDAT absolute encoder (as from SW 6)
NC MD 3944*
The rough encoder position in NC-MD 3944* currently being used is stored at the following
times:
• When an NC-MD file is stored (all NC-MD)
• On NCK Power On
• When "Parking axis" is deselected.
Linear axes, encoder on motor
The new maximum traversing range is derived from the set position control resolution. Other
limitations other than those mentioned above are not necessary.
Rotary axes, encoder on motor
In order to also avoid an error when determining the actual position of endlessly rotating rotary
axes (endless traversing range) within one or 16 revolutions, the denominator of the gear
encoder/load must be entered as NC-MD 3940* during start-up of the machine.
Example: Gearing 33/59:
59 encoder revolutions produce 33 load revolutions
MD 3940*=59
If the numerator and denominator of the gear have a common divisor, the denominator should
be reduced by this divisor. An example is given in the description of NC-MD 3940*.
Service display
To provide a control for the operator, the number of ENDAT absolute encoder overflows are
displayed in the axis service display.
12–92
© Siemens AG 1992 All Rights Reserved
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SINUMERIK 840C (IA)