A range of Escon controllers from Maxon that are small but powerful 4- Quadrant PWM servo controllers for the highly efficient control of permanent magnet activated DC motors. The controllers are reliable and are protected against overcurrent, under and overvoltage, excess temperature, short circuits in the motor cable, voltage transients and can also help protect both load and motor with protected digital inputs and outputs and an adjustable current limitation. The brushless DC motors have various operating modes which include speed controller (closed loop) which compares the actual speed signal with an applied set value. In case of deviation, the speed is dynamically readjusted, and speed controller (open loop) which feeds the motor with a voltage proportional to the applied speed set value.