Item Type: Speed Controller_x000D_ Input Voltage: 12-50VDC_x000D_ Maximum Current: 20A_x000D_ Speed Regulation Mode: PWM_x000D_ The Base Frequency has 3 Levels: The jumper shorts the left 2 pins is 2.1KHZ, the 2 short pins on the right are 2.9KHZ, and the 3 pins are short-circuited 11.1KHZ. The default is 2.9KHZ when shipped_x000D_ 2 Control Methods: Control whether the motor is controlled manually by an jumper switch or an external PWM signal is connected to the control card or PLC. External PWM input requirements are: Level 3.5-12V VPP, frequency 1K-5KHZ, duty cycle is 0% -93%_x000D_ Input Interface Specifications: The internal resistance is 330 ohms when connected to a PLC. To connect a 1.5-2.7K ohm resistor in series. Connect directly to a 5V level motion control card such as MACH3._x000D_ Alarm Output Interface Specification: The Maximum Driving Current is 12MA. _x000D_ Super High Power Control: Maximal 20A, it is recommended not to exceed 15A