Most sensors put out some sort of analog signal a voltage, current, or resistance that varies in a fixed relationship to a physical parameter. Instrumentation that converts the signal to engineering units must know a few things about what parameters to expect from the sensor. That's because full-scale range, sensitivity, connection schemes, and other factors all vary greatly from one kind of sensor to another. The end result is that it takes some effort to match up sensors with monitoring electronics. This configuration process may be no big deal when there are only a few sensors involved. But it can be problematic when gangs of sensors get wired into multichannel measurement systems.A smart sensor is simply one that handles its own acquisition and conversion of data into a calibrated result in the units of the physical attribute being measured. IEEE 1451.4 defines a relatively simple, straightforward mechanism for adding smart, plug and play capabilities to traditional analog sensors. Without adding any new hardware to the system, these plug and play sensors can bring real, immediate benefits in ease of use and productivity to any measurement and automation system that uses sensors.