A compression device particularly suited for DVT prophylaxis includes a disposable wrap and a re-usable controller removably mounted on the wrap to apply a tensioning force to the wrap when it is encircling the limb of a patient. The wrap includes a strap wrapped around an electric motor-driven pulley, with an encoder to determine the amount of rotation of the pulley and a current sensor to determine the current load on the motor during operation. A pretension protocol sets the pulley of the wrap at a proper frap position so that the wrap can properly execute a DVT prophylaxis protocol.