Sensor system for safety of humans around machines

摘要

The system has sensors of a light barrier type that have an optical transmitter (14) and a gap to a receiver (15) such that any interruption changes the output. The sensors are coupled (4) by interfaces (7) to a bus (4) that has a switched connection to duplicated processors (9,10) to allow an evaluation to take place. This results in alarm conditions being signalled if an individual triggers a sensor. The sensors are accessed on a polled basis by a programmable controller.