Abstract: A safety device for monitoring at least one machine is provided that has at least one sensor for generating sensor data on the machine and a processing unit for the sensor data that is connected at least indirectly to the sensor and to the machine, that is configured as a performance environment having at least one computing node that is configured to allow a plurality of logic units to run on the at least one computing node, wherein at least one logic unit is configured as a safety function unit for a safety directed evaluation of the sensor data and at least one logic unit is configured as a diagnostic unit for monitoring the at least one safety function unit, In this respect the at least one safety function unit is configured to transmit status reports and performance reports to the diagnostic unit and the diagnostic unit is configured to recognize a safety related malfunction of the safety device in a status monitoring using statuses from the status reports and in a performance monitoring using the perfor