10 – Standard Interfaces

Publisher Summary This chapter focuses on various standard interfaces used in industrial applications. The IEEE 1451.2 is an open standard that provides a standard interface for sensors and actuators. It defines the electrical and interface protocol. IEEE 1451 sensors and actuators contain an embedded microprocessor on a module called a Smart Transducer Interface Module (STIM). The STIM microprocessor handles the physical interface to the sensors and the standard interface to the controlling system. IEEE 1451 is a 10-wire, synchronous, serial interface. Signals include +5 V, ground, data-in and data-out lines, a clock, an interrupt, and other signals. IEEE 1451 specifies that each STIM have a transducer electronic data sheet (TEDS). This tells the controlling system certain parameters about the transducers on the module, including upper and lower range limits, warm-up time, calibration information, and timing information. Information passed from an IEEE 1451 STIM must be in standard units. The actual sensor may be measuring temperature, voltage, current pressure, velocity, or any other real-world parameter.