Stepper Motor Driver Overview  

The CMD-2ED-SA has two built-in microstep drivers, allowing the controller to directly drive 2 stepper motors.  

On this page:

Microstep 

The CMD-2ED-SA has 4 microstepping options including full step, 1/2 step, 1/4 step, and 1/8 step. In general, the number of microsteps per revolution can be determined by the follow equation, where "DEGREE" is the full step angle of motor and "USTEP" is the microstep setting. 

 

Micosteps/Revolution = 360° / (DEGREE * USTEP) 

 

For example, using a 1.8° motor and a microstep setting of 1/8, the number of microsteps/revolution would be [360° / (1.8° * 1/8)] = 1600. 

Driver Current 

The CMD-2ED-SA will have a maximum rated current output of 1.5A. The current settings should not exceed the rated current of the motor being used. Setting the driver current higher than the maximum rated current will overheat and potentially damage the motor.  It is recommended to use a current setting that is in the range of 60-80% of the maximum rated current for the motor. 

Configuring the Driver Current and Microstep 

The CMD-2ED-SA contains a series of jumpers that are used to configure the microstep and driver current settings.  

 

Figure 5.0 

 

To set the current, open up the top cover.  There are two dual row jumper headers JP1 (for X axis) and JP2 (for Y axis).    

 

There are four preset current settings: 0.8A, 0.7A, 0.5A, and 0.4A.  Any of these current setting can be selected using a jumper. 

 

For custom current setting, use the following formula to get the resistor value and solder across the custom current setting pins. 

 

Resistor Value = [4167 / Current (A)] - 1000 

 

For example, to set the current to 0.3A, resistor value will be 12.9K Ohm. 

 

To set the microstep, use the SW1 (for X axis) and SW2 (for Y axis) headers. 

          

 

MS1 

MS2 

1/8th microstep 

Open 

Open 

¼ microstep 

Open 

Close 

½ microstep 

Close 

Open 

Full step 

Close 

Close