| CPC G05B 19/048 (2013.01) | 7 Claims |

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1. A safety signal output device that monitors electrical signals of a plurality of systems input from a first device and outputs a safety signal based on a result of the monitoring, the safety signal output device comprising:
a connector to which a second device different from the first device can be electrically connected, wherein
the connector includes at least a first terminal, a second terminal, a third terminal, and a fourth terminal,
the safety signal output device outputs electrical signals with different timing to the first terminal and the third terminal respectively,
if an electrical signal of the electric signals is not input from the first device to the safety signal output device in at least one of the plurality of systems, the safety signal output device does not output the safety signal,
if the electrical signals are input to the safety signal output device from the first device in all of the plurality of systems,
during a first state in which electrical signals that correspond in timing to the output timing of the electrical signals to the first terminal are input to the safety signal output device from the second terminal, and electrical signals that correspond in timing to the output timing of the electrical signals to the third terminal are input to the safety signal output device from the fourth terminal, the safety signal output device outputs the safety signal,
during a second state in which electrical signals that correspond in timing to the output timing of the electrical signals to the first terminal are input to the safety signal output device from the fourth terminal, and electrical signals that correspond in timing to the output timing of the electrical signals to the third terminal are input to the safety signal output device from the second terminal, the safety signal output device outputs the safety signal, and
even when electrical signals are input to the safety signal output device from the first device in all of the plurality of systems, during a state different from either the first state or the second state, the safety signal output device does not output the safety signal.
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