A Hybrid Modular Control and Acquisition System.

In this paper we describe the architecture and the performances of a hybrid modular acquisition and control system prototype we developed in Napoli for distributed monitoring and control systems. The system, developed by our group within the framework of R&D for interferometric detectors of gravitational waves, is based on a dual-channel 18-bit low noise ADC and 16-bit DAC module at 800 kHz, managed by an Altera FPGA. The module is designed to be used standalone or mounted as mezzanine on a motherboard, in parallel with other modules. In particular, the modules can send/receive the configuration and the acquired/correction signal for control through a standard EPP parallell port to/from an external PC, where the real-time computation is performed. Experimental tests have demonstrated that this architecture allows the implementation of distributed control systems with a sustained sampling frequency up to f_c ≈80 kHz, using a standard PC for the control signals computation. Each module is also equipped with a 20-bit slow ADC necessary for the acquisition of an external calibration signal. The system is now being extensively tested in on a prototype of suspended optical interferometer for gravitational wave detection we are developing at the INFN in Napoli, made of three superattenuators of the same class of the TAMA Interferometer. [ABSTRACT FROM AUTHOR]