A Multi-Channel Fibre-Optic Link for Analog Telemetry

Control of an ion beam injector requires a reliable telemetry link for analog signals between the high voltage dome and ground. This paper describes a self-scanning, self-checking system capable of transmitting up to sixteen channels of analog data (in each direction) with eight bit resolution over a dual light link. The technique used is serial transmission of eight bit words using standard UART´s (Universal Asynchronous Receiver Transmitter) which provide much of the error detection and timing. Two versions, one stand-alone for manual control, the other an input/output interface board that plugs into a control microcomputer, have been designed. For sixteen channels, the data is updated every 3.2 milliseconds. The simple design and low parts count provide a low cost analog telemetry system.