To paraphrase Hood and rrc1962 - RTFM 

2) MOTOR CABLES: The motors connect to the G540 via male DB9 connectors. The four motor wires
connect to pins 6 and 7 for one motor winding, pins 8 and 9 for the other motor winding. The current
set resistor connects to pins 1 and 5. The motor cable should be a 4-conductor cable and it can be
shielded or unshielded. If a shielded cable is used, connect the shield to either pin 2, 3 or 4. Pins 2, 3 and
4 connect to ground inside the G540.

3) CURRENT SET RESISTORS: The current set resistor programs the axis drive current (0 to 3.5A) to
match the rated phase current of the motor being used with the axis. Each axis requires a current set
resistor. The resistor can be from 1/10 W to 1/2 W in size and 1% to 5% tolerance. The current set
equals 1,000 Ohms per Amp of motor current. Example: A 3.3A per phase motor requires a 3.3K resistor;
a 1.5A per phase motor requires a 1.5K resistor.

Cheers

Ian