Technical manual
SMCP33
Connections and circuits
3.6 Encoder
connection
Optional encoder
An optional encoder can be connected to the stepper motor control.
By default, the closed-loop control for a three-channel encoder is set up with 500
pulses/revolution in an 1.8° stepping motor. With an 0.9° stepping motor, you should
use an encoder with 1000 pulses/revolution to achieve the same control quality.
Depending on the application, it may make sense to use higher encoder resolutions
(up to max. 2000 pulses/revolution) to improve control quality or to use a lower
resolution (min. 200 pulses/revolution) for low-cost applications or for step monitoring
alone.
The following encoder resolutions can normally be processed by the controller: 192,
200, 256, 400, 500, 512, 1000, 1024, 2000, 2048.
Recommended:
Where possible, use Nanotec encoders with the order number
HEDS/HEDL-5541 Xxx.
If an encoder is
not
used, the "Disable" mode must be set in the <Error correction>
tab in the "Rotation Direction Mode" selection menu. See the separate manual on
NanoPro.
Using encoders with line drivers
The encoders of the HEDL series with line drivers output an inverted signal in addition
to the encoder signal; this leads to better interference immunity and is especially
recommended for long lines lengths.
The differential signal can be evaluated with a line driver/encoder adapter.
The following figure shows the input circuit of the encoder for channel A (Ch A) with an
inverted signal (Ch A\).
The SMCP controllers themselves currently cannot evaluate the differential signal,
meaning that only the channels A, B and I need to be connected to perform position
monitoring. We recommend shielding and twisting the encoder line to minimize
interference with the encoder signal from the outside.
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Issue: V 1.1 - 01.02.2010