Abstract: A PLC communication system includes a PLC; a plurality of devices; three or more communication processing nodes that are provided respectively in the PLC and the devices to allow the PLC to communicate with each of the devices; and a plurality of communication lines that connect the communication processing nodes to each other to allow data communication. The PLC detects an incommunicable state between two of the communication processing nodes. The PLC communication system further includes a display device, and in a case where there are a plurality of types of incommunicable states detected by the PLC, the display device displays a portion where communication lines constituting the incommunicable states among the plurality of communication lines overlap with each other, as a line failure portion.

Abstract: A PLC communication system includes a PLC; a plurality of devices; three or more communication processing nodes that are provided respectively in the PLC and the devices to allow the PLC to communicate with each of the devices; and a plurality of communication lines that connect the communication processing nodes to each other to allow data communication. The PLC detects an incommunicable state between two of the communication processing nodes. The PLC communication system further includes a display device, and in a case where there are a plurality of types of incommunicable states detected by the PLC, the display device displays a portion where communication lines constituting the incommunicable states among the plurality of communication lines overlap with each other, as a line failure portion.

Abstract: A lens barrel includes: a holding frame; a cam ring rotatable relative to the holding frame around a rotational axis substantially parallel to an optical axis of an imaging optical lens system; and a cam follower and a cam groove that engage with each other so that the holding frame and the cam ring move relative to each other along the optical axis when the holding frame and the cam ring are rotated relative to each other.

Abstract: A lens barrel includes: a holding frame; a cam ring rotatable relative to the holding frame around a rotational axis substantially parallel to an optical axis of an imaging optical lens system; and a cam follower and a cam groove that engage with each other so that the holding frame and the cam ring move relative to each other along the optical axis when the holding frame and the cam ring are rotated relative to each other.

Abstract: There is disclosed a lens barrel including a fixed frame, a rotary frame rotatable with respect to the fixed frame to advance or retract in an optical axis direction, and a rectilinear guide frame rotatable relative to the rotary frame to displace integrally with the rotary frame in the optical axis direction. In this structure, a front end portion of the rectilinear guide frame on a subject side in the optical axis direction is exposed from the rotary frame.

Abstract: There is disclosed a lens barrel including a fixed frame, a rotary frame rotatable with respect to the fixed frame to advance or retract in an optical axis direction, and a rectilinear guide frame rotatable relative to the rotary frame to displace integrally with the rotary frame in the optical axis direction. In this structure, a front end portion of the rectilinear guide frame on a subject side in the optical axis direction is exposed from the rotary frame.