A digital long pulse integrator

A prototype digital integrator with very long integration capabilities has been developed and field tested on an inductive magnetic sensor on the DIII-D tokamak. The integrator is being developed for use on ITER with a pulse length of 1000 s, and has direct applications for other long pulse tokamaks. Inductive magnetic sensors are routinely used on existing tokamaks, are well understood, and are extremely robust, however, they require integration of the signal to determine the magnetic field strength. The next generation of tokamaks, will have pulse lengths of 1000 s or longer, require integrators with drift and noise characteristics compatible with the very long pulse lengths. This paper will discuss the architecture, algorithms, and programming of the long pulse integrator (LPI). Of particular interest are the noise control and the built-in offset correction techniques used in this application.