METHOD OF FAST SWITCHING BETWEEN DEVICES

A safety input device for use in a single-wire safety system comprises a fast-switching architecture that allows a safety signal to propagate through the safety device to downstream devices with negligible delay. Rather than placing the signal processor in-line between the signal input and output terminals of the safety device, an electronic switch is placed between the input and output terminals. A signal processor in parallel with the switch monitors the incoming signal and closes the switch if the safety signal is absent, effectively shorting the input and output terminals and allowing the incoming safety signal to pass substantially instantaneously. Loss of the safety signal at the input terminal is immediately reflected by the loss of safety signal output at the output terminal, eliminating processing delay between loss of the safety signal at the input terminal and cessation of the output signal at the output terminal.