Control circuitry for photoelectric components of light barrier - switches components in sequence in multiplex process and detects functional error or fault

摘要

The photo-electric components (16) are connected in matrix-format to decoder (7, 8) outputs (9, 10). The decoders work independently from each other with processors (micro P1, micro P2) that form the control arrangement. At least one first decoder (7) with n outputs is connected to one terminal (17) of each component (16) forming a matrix group of m photo-electric components. At least one second decoder (8) with m outputs is connected to the other terminals (19) of the matrix group. The first decoder is controlled by the first procesor and the second decoder by the second. The control signals for the first decoder are also supplied to the second processor and the control signals for the second decoder are also sent to the first processor for registration of the control process. USE/ADVANTAGE - Protection of machine operatives against touching moving parts, e.g. if any of the photo-electric components are covered by a hand the machine is immediately switched off.