User`s manual

ROBOT . HEAD to TOE

Product User’s Manual – SD02B

5. INSTALLATION (HARDWARE)

5.1 Connecting Driver to a Stepper Motor

Most unipolar stepper motor comes with 5 or 6 wires. As shown in the following left figure,

there will be 2 wires (1 and 2) which act as the common terminal for coil a and coil b. If these

2 wires (1 and 2) are not used, it will become bipolar stepper motor as shown in figure on the

right.

Before connection can be made, please determine the correct wiring for stepper motor. In

general, 2-phase stepper motors can have 4, 5 or 6-wire leads, not including any (optional)

encoder lines. The best solution is to obtain the pin out from the motor manufacturer. If user

does not have access to the pin out, then the following procedure will help in determine

wiring of the 2-phases stepper motor.

Some stepper motors have a motor case ground that can be tied to the ground of the system. It

is usually a black wire, and it will add one additional wire to the overall count (4 coil wires +

1 casing ground = 5 wires total).

• If the stepper has four coil wires:

a. Each of the two phases (X and Y) should have the same resistance when

measured with a multi-meter. When measuring the resistance across one wire

from each of the two phases (between X and Y), the resistance should be

infinite because the circuit is open. Locate the two pairs of wires that represent

the two phases, and both pairs of wires will have similar internal resistance.

b. Connect each phase to SD02B and ignore the polarity (+/-), for now. User has

a 50% chance of guessing right.

c. Press Test button on SD02B to rotate the motor. It should rotate in CCW

(counterclockwise) by looking at the motor shaft. If the motor rotates in the

wrong direction, switch either phase X and !X or Y and !Y (effectively

reversing directions).

• If the stepper has six coil wires, then each phase has a center tap wire:

a. The center tap wire should have half the internal resistance of the full phase.

The easiest option is to use a multimeter to find the two pairs of wires that

have the maximum resistance.

Unipolar stepper motor Bipolar stepper motor