Serial/Digital Interface at 1200 baud (SDI-12)
SDI-12 is an asynchronous, standardized serial communications protocol for intelligent sensors that monitor environmental data. Furthermore, SDI-12 is the standard for interfacing battery powered data recorders with microprocessor-based sensors, providing a means by which to transfer measurements from sensor to data recorder.
In short, intelligent sensors typically take a measurement, make computations based on the raw sensor reading, and output the measured data digitally in engineering units.
SDI-12 is used in applications with these requirements:
- Battery powered operation with minimal current drain
- A single datalogger with multiple sensors on a single channel
- Microprocessor based sensors that perform complex calibration algorithms or make internal computations
As the instruments typically require low power, are used in remote locations, and often communicate with dataloggers, SDI-12 is ideally suited for several Campbell Scientific products including:
- CS225 Temperature String
- CS230 Temperature Profiler
- AVW200 2-Channel Vibrating-Wire Interface
- CS451/CS456 Submersible Pressure Transducers
- CS215 Temperature and Relative Humidity Probe
- SR50A Snow Depth Sensor
Example:
The SR50A takes a series of sonic range and temperature measurements, processes them, and outputs corrected snow depth in cm or other selected units.