EVOLUTION IN CONTROLS METHODS FOR THE
SPS POWER CONVERTERS

A. Dinius, J.G. Pett - CERN
J. Brazier* - Brazier Systems and Consultants


In common with much accelerator specific material, there is a constant need to improve both hardware and software for power converter control. Maintenance and performance improvements of older systems have become extremely tedious and in some areas impossible. By using modern real-time software and the latest high-performance processors, such problems should be substantially reduced.

This paper describes the software concepts and the hardware chosen for the upgrade of the existing facilities. Using the UNIX compatible LynxOS real time kernal, running on a PowerPC 603 in a VME environment, this new approach provides excellent performance while retaining the desired flexibility for future enhancements.

The 64 channel system is implemented as a set of cooperating processes, several of which are multi-threaded. Processes include analogue function generation, analogue measurement and digital I/O, all of which are accurately scheduled by the accelerator timing system. This generalized structure, which performs complex sequences of operations, is described in detail, as well as how it can be adapted to a wide variety of accelerator tasks.