Remote Data Acquisition for SPS 352 MHz Superconducting Cavities

The SPS Machine is equipped with four SuperConducting (SC) Cavities. These are used to accelerate the beams during the electron and positron cycles of LEP. During the last two years the control system for these cavities has been upgraded to the LEP standard environment but, as the diagnostic capabilities were not sufficient to ensure their reliable operation, it was decided to build a Data Acquisition system based on commercial products. The present system is based on National Instrument PXI (an extension to CompactPCI for instrumentation) with 166 MHz Pentium running Windows NT and Labview5.1. In order to meet the user requirements, in terms of portability and speed, a client/server approach has been used. The Server can acquire 16 signals at a rate of 1 ms during the whole SPS supercycle. The Client is composed of a virtual oscilloscope interface (one or four channels) with on-line signal and timing selections and automatic data and user setting storage capabilities. The Client can run on the two platforms used at CERN (PC and HP/UX).