Design and research of an intelligent instrument and meters is one of important bottlenecks by which the new generation of industrial manufacturing technology makes a breakthrough. Lon intelligent transducer is based on LonWorks bus, and it can makes standard analog signal, nonstandard weak analog signal and pulse signal into digital signal and communicates with other intelligent instruments by bidirectional digital communication. The important feature of the transducer is the function of dealing with sensor failure, and it can continue to output valid data when the senor gets into failure at some time. So the function can keep the controlled system stable and safety.