Signal conditioning electronics and packaging for the Alcator C-MOD tokamak

Engineers and physicists are collecting more data and looking at more signals with each new fusion machine. Most of these signals need some form of processing, amplification, integration, isolation, etc. An economical way of handling signals is needed that avoids the redundancy of individual power supplies and packaging. The system has to accommodate both large and small numbers of channels with a variety of inputs and outputs. This paper reports on a design utilizing industry-standard EURO card packaging, connected via ribbon cable to a custom I/O backplane, and accommodates the many different circuits to be used on ALCATOR C-MOD. The chassis approach eliminates packaging, powering, and mounting problems associated with one of a kind circuits and allows dense packaging of multiple circuits. The separate I/O backplane allows easy removal and replacement of circuit cards, while leaving front panel space available for circuit-specific indicators. The DIN pin-and-socket connectors are considerably more robust and reliable than edge connectors. The pin-out was chosen to allow up to four circuits per card, allowing up to eighty channels in one 5 1/2 inches tall, rack mountable chassis. The 11 inch I/O backplane provides the user with Lemo and screw terminal connnectors