PSR8078 User Manual
REV1.0 9
setting closest to your motor’s required current.
Peak Current
RMS Current
SW1
SW2
SW3
2.8A
2.0A
ON
ON
ON
3.5A
2.5A
OFF
ON
ON
4.2A
3.0A
ON
OFF
ON
4.9A
3.5A
OFF
OFF
ON
5.7A
4.0A
ON
ON
OFF
6.4A
4.6A
OFF
ON
OFF
7.0A
5.0A
ON
OFF
OFF
7.8A
5.6A
OFF
OFF
OFF
Notes:
Due to motor inductance, the actual current in the coil may be smaller than the
dynamic current settings, particularly under high speed condition.
Standstill Current
SW4 is used for this purpose. OFF means the standstill current is set to be half of the
selected dynamic current. ON means standstill current is set to be the same as the selected
dynamic current.
The standstill current of the stepper drive PSR8078 will automatically be reduced to 50% of
the selected dynamic current setting one second after the last pulse. Theoretically, this will
reduce motor heating to 25% (due to P=I
2
*R) of the original value. If the application needs a
different standstill current, please contact PrimoPal Motor.
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 Pulse/Direction 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.
PSR8078 User Manual
REV1.0 10
9. Typical Connections
A complete stepper system should include stepper motor, stepper drive, power supply and
controller (pulse generator). The following figures are two typical connections of the stepper
drive PSR8078.
Figure 9: Typical connection
