Eight channel-16 bit, bidirectional analog to digital monitoring and control system

The DIII-D tokamak facility is currently upgrading its electron cyclotron resonance heating system. The new system is based on 110-GHz gyrotrons developed by Varian. As part of this upgrade, the superconducting magnet power supplies were required to be remotely controlled and monitored accurately. The 110-GHz gyrotron superconducting magnet has eight coils, which are energized by current regulating power supplies. An analog-to-digital (A/D) system was designed to allow remote coil current monitoring and power supply programming. The A/D system is an eight channel multiplexed, 16-b, bidirectional, fiber optically linked, A/D telemetry system. Design concerns and tradeoffs are discussed, as are the results of in-system use