摘要 |
In a system for the transmission of light from a process measuring device to an alarm actuating circuit, an optical fibre (14) is positioned adjacent each process monitoring location and transmits light therefrom to a remotely located matte screen (12) from which it is reflected to a pair of optical fibres (16, 18). The optical fibre (16, 18) transmit the light to respective optical diodes (20, 22) which are selectively actuated in response to the colour of the light being transmitted and which, in turn, selectively actuate an alarm circuit connected thereto. |