A large memory {VME} data acquisition system for the jet heterodyne radiometer upgrade

N Cruz; J Sousa; R Pereira; x Combo; C.A.F Varandas; M Beldishevski; S Dorling; B Alper

Key information

Authors:

N Cruz (Nuno Sérgio Castelo Branco da Cruz); J Sousa (Jorge Rosa Lopes de Sousa); R Pereira; x Combo; C.A.F Varandas; M Beldishevski; S Dorling; B Alper

Published in

2004

Abstract

A large memory {VME} data acquisition system was developed for the {JET} heterodyne radiometer upgrade, which is capable of acquiring/storing 576xa0;MB of data per {JET} pulse. The implementation of the system integration software, which includes a CGI-based control interface and the data acquisition software is described as well as the development and architecture of the transient recorders. The system maximum data throughput is 288xa0;MB/s when all the 48 channels acquire at the maximum rate of 3xa0;MSPS. The system hardware is composed by the following components: (i) A {VME} controller module, with a Pentium {III} processor running Linux, 128xa0;MB of RAM, 100xa0;Mbits/s Ethernet channel and a 40xa0;GB disk; (ii) Six on-site-developed transient recorder modules, each having 8 input channels, 12 bit resolution, 6xa0;MSample/channel of memory and sampling rate up to 3xa0;MSPS. Optimal {VME} device drivers were developed to minimize the data transfer time to the local disk. The acquired data on disk is remotely available through a {HTTP} server. The system has been reliably in operation since January 2003.