A field device for determining or monitoring a process variable in process automation. The field device includes: sensor, which works according to a defined measuring principle; and a control/evaluation unit, which conditions and evaluates measurement data delivered by the sensor along at least two equal valued measuring paths as a function of a safety standard required in a particular safety-critical application. The control/evaluation unit is embodied, at least partly, as a reconfigurable logic chip, with a plurality of partially dynamically reconfigurable, function modules. The control/evaluation unit so configures the function modules in the measuring paths as a function of the defined safety-critical application, that the field device is correspondingly designed to the required safety standard.