AMDI has developed a Remote Access Sensor Link (RASL) terminal under a joint venture with North Star Science and Technology.

The unit consists of a satellite terminal and an interface board. The interface board provides signal conditioning, timing, and interface functions between the satellite terminal and an external sensor or sensor suite. Sensor data is sampled, packed, and transmitted via the satellite terminal to a www data portal from which it can be retrieved in real time.

The system can be configured to transmit at periodic intervals, event-driven (when a parameter falls outside a pre-programmed range), or a combination of both periodic and event driven. A data logging function runs in the background and allows for storage of sensor parameters at a rate higher then, and independent of the transmission rate.

The first application of this technology is for water monitoring. The RASL has been interfaced to a series of water monitoring sondes manufactured by YSI Incorporated, Marion, MA. The most commonly monitored parameters are Depth, Dissolved Oxygen, Specific Conductivity, Temperature, pH, and Turbidity. Other parameters can be output by the sonde or computed from those listed above.

The interface to the YSI sonde is SDI-12. Other applications are in development. Available serial interfaces include SDI-12, RS-232, and RS-485. Signal conditioning is available on-board to handle a variety of analog and digital functions. Custom configurations are also available.