NinjaCalcIEEE-488 (GPIB)
IEEE-488 is a parallel 8-bit short-range multi-master communications bus. It is more commonly known as GPIB (General Purpose Interface Bus).
| Property | Value |
|---|---|
| Serial/Parallel | Parallel |
| Drive Type | Single-ended |
| Num. Signal Lines | 16 (8 data, 3 handshake, 5 bus management) + 8 GND |
| Duplexity | Full |
| Connection Topology | Multi-master, star or forked |
| Layers | Initially, only the physical and electrical layers were specified. The commands/message format varied between manufacturers or even between devices made by the same manufacturer. Later on standard commands were specified (IEEE 488.2) |
History
In the late 1960’s, Hewlett-Packard developed the HP Interface Bus (HP-IB) to connect the automated test and measurement instruments they manufactured to computers and other controllers. HP licensed the HP-IB technology to other manufacturers, and as the bus became popular, it became known as the General Purpose Interface Bus (GPIB)1.
In 1975 IEEE standardized the GPIB as Standard Digital Interface For Programmable Instrumentation (IEEE 488). In 1987 IEEE released 488.2 as Standard Codes, Formats, Protocols, and Common Commands which specified basic device-independent syntax and messages.
488.2 standardised the syntax and a set of common commands, but not the commands that actually drive a measurement — those were still manufacturer-specific. SCPI was released in 1990 to close that gap, layering a standard instrument-class command tree on top of 488.2. Unlike 488.2, SCPI does not mandate a transport, and today it is used over USB, Ethernet and RS-232 far more often than over GPIB itself.
Although initially designed for connecting instrumentation to computers, in 1977 HP also used the GPIB bus inside it’s Commodore PET range of personal computers to connect peripherals1. However this was quickly replaced with faster buses such as SCSI.
In instrumentation, GPIB has generally been replaced with more recent communication protocols such as USB and Ethernet for new instrumentation.