CHEAT SHEET For SD540B - PWM Motor Controller for FRC

If you are new to SD540B, please refer to this page for related information, and save this URL for future reference.


Key Features

  • Load capacity: 60 amps continuous, 100 amps peak
  • Passive Cooling
  • Bidirectional limit switches
  • Power, direction and status indicator LEDs
  • Brake/coast and direction selection with flip of a switch
  • Field upgradable firmware


SD540B Related Documents

Download User Guide PDF here.


SD540B Software Interface

SD540B uses PWM signal to operate the motors, any library (LabVIEW, C++, Java, etc) that provides PWM API will work with SD540B.


SD540B Electrical Connections

Power Input and Output terminals are color coded as in picture below.

PWM cable attaches on three Top-Left pins as shown in the picture below.


SD540 Electrical connections

If your design uses Limit Switches:

There is provision to attach two limit switches, High and Low. Connect them to bottom left pins as in picture above. (Read more about Normally Open vs Normally Closed configuration in DIP switches section below).


How to Mount SD540B on your robot

Single Unit Controller:

Mounting SD540 - screws size

The SD540B comes with 1/2 inch long screws.


Configuration of DIP Switches

There are 6 DIP switches at the bottom of your device. You can use these switches to change behavior of SD540 to get maximum benefit for your robot design.

  • PWM Switch must be set to Position PWM (left).
  • Rev/Fwd Switch will change the direction of the motor rotation, and role of High and Low Limit switches.
  • LimL Switch will change behavior of Low Limit switch from Normally Open to Normally Closed.
  • LimH Switch will change behavior of High Limit switch from Normally Open to Normally Closed.
  • Brake/Float Switch will Brake or Float the motor when stopping.
  • Calibrate/Run Switch for normal operation, keep this switch to Run Position (right).

SD540 DIP Switches

Calibrate Switch can be used to calibrate the PWM signal (if required).

Device is calibrated at factory for RoboRIO, so you do not need to calibrate for RoboRIO.

If you plan to use with a different controller, write to us for calibration instructions.


Troubleshooting SD540B

Power LED

This LED will turn Red when Power is supplied.

Motor LED

This LED turns Red in Forward direction and Green in Reverse direction.

PWM Signal LED

This LED turns Red when no valid PWM signal is detected, and turns Green when valid PWM signal is detected.



Single Unit Controller:

  • Length: 2.7"
  • Width 1.6"
  • Height: 1.2"


Performance Characteristics