SLS 2001 SMD

The SLS 2001 SMD card is a unipolar bi-level stepping motor driver, which can drive 4 phase motors with drive currents of up to 4 amps per phase (5A for extended version). It is designed for low electrical noise, high stepping rates and high efficiency (low heat generation).

Supply Voltage
Max. power requirements
Max motor current
4A per phase (5A for extended version)
Motor supply voltage
1V to 8V (DIP switch selectable in 1V steps)
Driving current
0.5A to 4A (DIP switch selectable in 0.5A steps)
Capable of driving four phase stepping motors with 6 or 8 leads in unipolar mode
Max. 20000 steps/sec
Motor ON/OFF TTL input
Motor ON/OFF switch on front panel (no current through motor coils)
TTL output of status of ON/OFF switch
Full/Half step switch (on the board)
Motor enable TTL input (disables driver, current through motor coils on, not available through OMS VME58 interface)
limits, home switch status and busy LEDs on front panel
100mm by 220mm
32pin male DIN 41612
Front Panel
Busy Led
Active when motor is stepping
+Limit Led
Active when motor has reached positive limit
Home Led
Active when motor has reached home switch
-Limit Led
Active when motor has reached negative limit The driver only displays limits!
ON/OFF Switch
Turns current to phases on or off DRIVE CURRENT DIP Switch: Selects drive current
Selects holding voltage FULL STEP/HALF STEP switch on board
Setting the motor parameters
The correct parameters for a specific motor can be taken from the manufactures datasheet. It should be noted that most current values are given for motors in bipolar mode, unless otherwise noted. For motors running in unipolar mode, the value for the current is about 70% of that of motors in bipolar parallel wiring or about 150% of motors in bipolar serial wiring. This decreases the torque by about 30% (in a unipolar motor as compared to a motor in bipolar wiring). In order the set the motor parameter correctly a basic understanding of the bilevel drive is needed
When the motor is stopped (holding) only the MOTOR VOLATAGE is supplied to the motor. This MOTOR VOLATAGE is set by the VOLTAGE DIP switch. This voltage can be set lower than the rated voltage of the motor to reduce the heat load in the motor but it also affects the step performance (see next point). For long motor cable one also needs to take the voltage drop in the cable into account. See the following chart to estimate the voltage which needs to be added (The chart takes both the phase wire and the return wire into account).
When the motor is stepping, the full supply voltage (+48V driving voltage) is supplied to the motor until the DRIVE CURRENT is reached in the phase. This current is set with the DRIVE CURRENT DIP switch. The driver then switches to the MOTOR VOLATAGE for the remaining duration of the step