Abstract: An object detection method comprises transmitting a plurality of signals from a transmitter into a region; measuring a plurality of signals, each corresponding to a respective one of the plurality of the transmitted signals, received by a sensor; determining whether each of the plurality of received signals satisfies a condition (such as that a received signal is above a threshold level for indicating that an object is located in the region, or below a threshold level for indicating that an object is not located in the region); determining whether noise of at least a threshold amount is present; and determining whether an object is located within the region depending on whether at least a number of received signals meet the condition, the number being different when noise of at least a threshold amount is determined to be present than not present. For example, the required number of received signals that meet the condition when noise is present can be higher than when noise is absent.

Abstract: The present invention involves a methodology for the interconnection of safety control modules used for the safeguarding of personnel around points and areas of hazardous machine operation. The system includes one or more safety control modules connected together so that the safety control modules communicate with each other using actively diverse safety control signals. The safety control modules are also connected to the machine safety control circuit so that the safety control modules can stop machine operation when one or more safety control modules are activated. The use of actively diverse safety control signals provides a control reliable system.

Abstract: The present invention involves a methodology for the interconnection of safety control modules used for the safeguarding of personnel around points and areas of hazardous machine operation. The system includes one or more safety control modules connected together so that the safety control modules communicate with each other using actively diverse safety control signals. The safety control modules are also connected to the machine safety control circuit so that the safety control modules can stop machine operation when one or more safety control modules are activated. The use of actively diverse safety control signals provides a control reliable system.