Siemens SINUMERIK FM-NC Installation And Startup Manual page 123

12.98 12.97
03.96
Rotary
EQN 1325 type encoders can represent 4096 revolutions. This means that the
detected positional value is unique over the maximum specified ranges:
absolute encoder
with wide
S
traversing range
S
S
Note
As from SW 4 the traversing range is identical with that of incremental encod-
ers.
The user must ensure that when the encoder is switched off (power off/on,
parking), the axis is moved by less than half the clearly representable absolute
encoder number range.
In this case, the software can reconstruct the new position by shortest-path
detection.
Otherwise position movements when the encoder is active is possible across
the whole traversing range without any limitations.
Limitations with
The following limitations apply to endlessly turning rotary axes with absolute
encoders:
rotary axes
S
S
For normal applications (encoder 1:1 on the load) there are no limitations for
endlessly turning rotary axes.
Note
The limitations described above are eliminated in software version 4 and
higher.
Any transmission ratios are permitted, the numerator and denominator must be
integers; the overrun compensation required for this is performed by the soft-
ware.
NC RESET After you have entered and stored all drive data sets, you must perform an NCK
Reset. The SF LED then goes out and the drives can be traversed after PLC
start-up (presetting of speed controller).
After the axis-specific velocity and traversing range limits have been adjusted,
the speed control preset values should be optimized.
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SINUMERIK 840D Installation and Start-Up Guide (IAD) – 04.00 Edition
6 Assigning Parameters to the Control and the PLC Program
Rotary axis, encoder on load: 4096 load revolutions.
Rotary axis, encoder on motor: 4096 motor revolutions.
Linear axis, encoder on motor: 4096 * effective spindle lead.
In the case of linear axis with an effective spindle lead of 10 mm, a travers-
ing range of 40.96 m is covered.
When the encoder is installed on the load, the load-sided actual value can
be processed only as modulo 1, 2, 4, 8, 16, ..., 4096 revolutions (only pow-
ers of 2 are allowed).
When the encoder is installed on the motor, the gearbox ratio with respect to
the load must be n:1 (n motor revolutions to 1 load revolution). For n also,
only powers of 2 are allowed.
6.9 Axes and spindles
6-123
6