A power machine comprising: a frame; a power system (104; 220) supported by the frame and configured to provide power for operating functions on the power machine; machine function components supported by the frame and configured to perform machine functions using power from the power system; a machine controller configured to control the application of power from the power system to the machine function components; an operator control system (260; 302) including a user input module (103; 303) configured to wirelessly communicate with the machine controller to communicate user input commands to the machine controller to control the machine function components and corresponding machine functions, characterised by the operator control system further comprising a mount on which the user input module can be positioned on the power machine, wherein the user input module is configured such that when positioned on the mount on the power machine the user input module communicates with the machine controller through a wired connection, and when the user input module has been removed from the mount the user input module communicates with the machine controller wirelessly through a wireless connection; and an operator proximity detection system configured to detect whether the operator is in close proximity to the power machine, when the user input module is removed from the power machine to wirelessly communicate with the machine controller, and to provide an output indicative of operator proximity information; wherein the machine controller is configured to control application of power from the power system to the machine function components partially as a function of the operator proximity information, the machine controller further configured to: determine whether the user input module is positioned on the mount; operate the power machine, using the machine controller, responsive to the user input commands from the user input module if the user input module is positioned on the mount; if the user input module is not positioned on the mount, determine (415; 420) using the operator proximity detection system whether the operator is proximate the power machine; prevent operation of the power machine responsive to the user input commands from the user input module if the operator is determined to be proximate the power machine. a frame; a power system (104; 220) supported by the frame and configured to provide power for operating functions on the power machine; machine function components supported by the frame and configured to perform machine functions using power from the power system; a machine controller configured to control the application of power from the power system to the machine function components; an operator control system (260; 302) including a user input module (103; 303) configured to wirelessly communicate with the machine controller to communicate user input commands to the machine controller to control the machine function components and corresponding machine functions, characterised by the operator control system further comprising a mount on which the user input module can be positioned on the power machine, wherein the user input module is configured such that when positioned on the mount on the power machine the user input module communicates with the machine controller through a wired connection, and when the user input module has been removed from the mount the user input module communicates with the machine controller wirelessly through a wireless connection; and an operator proximity detection system configured to detect whether the operator is in close proximity to the power machine, when the user input module is removed from the power machine to wirelessly communicate with the machine controller, and to provide an output indicative of operator proximity information; wherein the machine controller is configured to control application of power from the power system to the machine function components partially as a function of the operator proximity information, the machine controller further configured to: determine whether the user input module is positioned on the mount; operate the power machine, using the machine controller, responsive to the user input commands from the user input module if the user input module is positioned on the mount; if the user input module is not positioned on the mount, determine (415; 420) using the operator proximity detection system whether the operator is proximate the power machine; prevent operation of the power machine responsive to the user input commands from the user input module if the operator is determined to be proximate the power machine. determine whether the user input module is positioned on the mount; operate the power machine, using the machine controller, responsive to the user input commands from the user input module if the user input module is positioned on the mount; if the user input module is not positioned on the mount, determine (415; 420) using the operator proximity detection system whether the operator is proximate the power machine; prevent operation of the power machine responsive to the user input commands from the user input module if the operator is determined to be proximate the power machine.