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User Manual
Appendix C
GFK-1742F
Jan 2020
Position Feedback Devices
414
Appendix C:
Position Feedback Devices
Four
and
Series Digital serial encoder models function with the DSM314:
Table 90: Digital Serial Encoder Resolutions
8K
(8,192 cts/rev)
- No longer available on new motors
32K
(32,768 cts / rev)
- Standard on
β
Series motors
64K
(65,536 cts/rev)
- Standard on
α
Series motors
1000K
(1,048,576 cts/rev)
- Optional on
α
Series motors
Note:
The older “A” or “C” Series million count serial encoder will not operate with the DSM314. An
error will be reported if this encoder is connected.
For position control purposes, by default, the DSM314 treats all encoders as 8192
counts/rev. The additional resolution of 32K, 64K and 1000K encoders will still be used in
the digital servo velocity controller to provide smooth operation at low speeds. To use the
increased position feedback resolution, refer to the Tuning Parameters section of Chapter
4.
C-1
Digital Serial Encoder Modes
The Digital serial encoders can be operated in either Incremental mode or Absolute mode.
The mode is configured using the Feedback Mode selection in the configuration software.
Proper operation of the Absolute mode requires an external battery pack that must be
connected to the servo amplifier. Refer to the appropriate amplifier manual for selection
and installation of the battery pack.
C-2
Incremental Encoder Mode Considerations
The digital serial encoder can be used as an incremental encoder returning 8192 counts per
shaft revolution, with no revolution counts retained through a power cycle. The equivalent
of a marker pulse will occur once each motor shaft revolution. All Home Modes (Home
Switch, Move+, Move
–
) and Set Position %AQ commands reference the axis, and set the
Position Valid %I bit upon successful completion. The configured High Position Limit and
Low Position Limit are valid and the Actual Position %AI status word as reported by the
DSM314 will wrap from high to low count or from low to high count values. This is an
excellent mode for continuous applications that will always operate via incremental moves,
in the same direction. Home Offset and Home Position configuration items allow simple
referencing to the desired location.