Controller for a motor starter

The device has at least one evaluation unit for an external temperature sensor for the motor temperature, a current converter block (13) for measuring the power drawn by the motor, switching elements (11) and programmable control electronics (10) with a data memory (18) and for connection to the evaluation unit, current converter block and switching elements and, via an interface (14), to the bus system (2). The control electronics generate a control command for the starter from data received via the bus and switching states of the switching elements. Independent claims are also included for the following: a motor starter and a method of controlling a motor starter networked with a bus system.