FAIL-SAFE SCANNING CIRCUIT AND SENSOR OF MULTI-OPTICAL AXIS BEAM TYPE.

摘要

A fail-safe scanning circuit having a scanning output generating circuit (20) for generating continuously scanning output signals which are given to objects to be driven, and a failure sensing circuit (30) for sensing whether the scanning output state of the circuit (20) is normal or not. When an abnormality of the scanning output of the circuit (20) is sensed, the output of the failure sensing circuit (30) is made to stop. Also, using two such fail-safe scanning circuits (41, 42), a pair of a light emitting element and a light receiving element are driven to scan synchronously. Thereby, a sensor of a multi-optical-axis beam type is obtained as a fail-safe man-sensor in a system wherein machines and men work in the same space.