Nothing Good Lasts Forever, but Ieee 488’s Slow Decline Is Making the Venerable Instrument-interface Standard Seem Immortal

Like the character in the famous Monty Python sketch, IEEE 488 is not dead yet. The decades-old standard’s longevity is in question, however, and you probably have good reason to care about its fight for life. Whether you design test-and-measurement instruments, develop or implement systems that incorporate test-and-measurement products that others design, or simply use such products in your lab or test facility, the methods that instruments use to communicate with each other and with host computers matter a lot. The communications medium’s physical implementation, protocol, and instrument-specific command sets strongly influence instruments’ and systems’ speed and cost and the time EEs must spend programming and debugging test applications. In 1977, the IEEE adopted the bus structure and communication protocol that it named IEEE 488. Some others call it GPIB (general-purpose instrumentation bus). The bus’s original name was HPIB (Hewlett-Packard instrumentation bus). HP, which, in 1999, spun off its electronic test-and-measurement business as Agilent Technologies, was the largest manufacturer of such equipment, a market position that Agilent still enjoys. Even before the early 1980s ushered in the widespread availability of PCs, large numbers of minicomputers (remember them?) were in use controlling instruments and processing the data they generated. Until the advent of the HPIB, no standardized methods existed for interfacing instruments with computers. It’s only a slight exaggeration to say that no two instruments interfaced in the same way. The RS-232 serial-communication standard and the Centronics parallelprinter interface did a decent job of standardizing the computer side of the interface and even motivated some standardization on the instrument side. (RS232 ports became popular on slower instruments.) Still, because it was rugged and relatively speedy, was designed for NOTHING GOOD LASTS FOREVER, BUT IEEE 488’S SLOW DECLINE IS MAKING THE