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DMD870 Digital Stepper Drive User’s Manual
Motion Control Products Ltd.
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Standstill current setting
SW4 is used for this purpose. OFF means that the standstill current is set to be half of the
selected dynamic current, and ON means that standstill current is set to be the same as the
selected dynamic current.
The current automatically reduced to 60% of the selected dynamic current one second
after the last pulse. Theoretically, this will reduce motor heating to 36% (due to P=I
2
*R) of
the original value. If the application needs a different standstill current, please contact us.
8. WIRING NOTES
In order to improve anti-interference performance of the Drive, it is recommended to
use twisted pair shield cable.
To prevent noise incurred in PUL/DIR signal, pulse/direction signal wires and motor
wires should not be tied up together. It is better to separate them by at least 10 cm,
otherwise the disturbing signals generated by motor will easily disturb pulse direction
signals, causing motor position error, system instability and other failures.
If a power supply serves several drives, separately connecting the drives is
recommended instead of daisy-chaining.
It is prohibited to pull and plug connector P2 while the Drive is powered ON, because
there is high current flowing through motor coils (even when motor is at standstill).
Pulling or plugging connector P2 with power on will cause extremely high back-EMF
voltage surge, which may damage the Drive.