Hybrid control and acquisition system for remote control systems for environmental monitoring

In this paper we describe the architecture and the performances of a hybrid modular acquisition and control system prototype for environmental monitoring and geophysics. The system, an alternative to a VME-UDP/IP based system, is based on a dual-channel 18-bit low noise ADC and a 16-bit DAC module at 1 MHz. The module can be configured as stand-alone or mounted on a motherboard as mezzanine. Both the modules and the motherboard can send/receive the configuration and the acquired/correction data for control through a standard EPP parallel port to a standard PC for the real-time computation. The tests have demonstrated that a distributed control systems based on this architecture exhibits a delay time of less than 25 us on a single channel, i.e a sustained sampling frequency of more than 40 kHz (and up to 80 kHz). The system is now under extensive test in the remote controls of seismic sensors (to simulate a geophysics networks of sensors) of a large baseline suspended Michelson interferometer.