The jumpers and trimmers are inside the enclosure: remove the cover (four M2.5 screws) with all power off. Use 1.27 mm (0.05 in) pitch jumpers; two spare jumpers are supplied.

On this page

• Motor Current (J13 X axis, J12 Y axis)
• Microstep Resolution (J9 X axis, J6 Y axis)
• Power Sources

Motor Current (J13 X axis, J12 Y axis)

Set the current to 60–80 % of the motor’s rated current and never above it. Setting accuracy is about ±8 %†.

Always fit a jumper. With no jumper on J12/J13 the driver current rises to about 2.5 A, above the 2.0 A rating of the unit.

Custom current (ADJ). Move the jumper to ADJ, calculate VREF = Ipeak / 0.78 (for example 0.51 V for 0.4 A, 1.54 V for 1.2 A; do not exceed 2.56 V = 2.0 A), measure between TP3 (X) or TP2 (Y) and TP1 (GND) with motor power on, and turn RV2 (X) or RV1 (Y) until the meter reads VREF.

Microstep Resolution (J9 X axis, J6 Y axis)

Hardware setting (PMX-2ED-SA compatible, full to 1/8 step; the controller holds the third mode line low in this mode). MS1 is the jumper pair nearer the back of the unit, MS2 the pair nearer the front.

Software setting (factory default: no jumpers fitted on J9/J6). Set the resolution per axis with the MSR command: 1 = 1/2, 2 = 1/4, 3 = 1/8, 4 = 1/16, 5 = 1/32, 6 = 1/64, 7 = 1/128. The resolution can be changed on the fly. With CMD-2CR firmware, IO27–IO29 set the X axis and IO30–IO32 the Y axis. A fitted jumper overrides the software setting for its line.

Microsteps per revolution = 360° / (motor step angle × resolution); for example a 1.8° motor at 1/8 step gives 1,600 microsteps per revolution.

Power Sources

There is no automatic source selection. The logic (J3) and motor (J5) supplies are independent and both are required; USB VBUS is sensed but not used for power.