Real World Instrumentation with Python

GPIB/IEEE-488

The General Purpose Interface Bus (GPIB) was developed by Hewlett-Packard in the late 1960s to interface HP test equipment with other test instruments, HP printers, and HP’s line of laboratory minicomputers and mass data storage devices. Originally known as the Hewlett-Packard Interface Bus (HPIB), it was given an IEEE standards designation in 1975.

Although GPIB (HPIB at the time, actually) was used in the late 1970s with some HP computer equipment to interface large external disk drives and line printers, it never really caught on as a data peripheral interface standard. It was, and still is, most commonly found in test and data acquisition equipment.

GPIB/IEEE-488 Signals

GPIB is a type of parallel interface that contains data, command, and interface signal lines in one cable. GPIB addressing allows up to 15 devices to share a single 8-bit parallel data bus. The maximum data rate is around 8 MB/s for the latest versions of the standard.

Internally, GPIB uses 12 lines for various signals and 12 lines for shield and ground connections. Table 7-6 lists the GPIB signals, and Figure 7-37 shows the pin-out of a GPIB connector.

Table 7-6. GPIB signals

Signal	Pin	Function
DIO1	1	Data/command
DIO2	2	Data/command
DIO3	3	Data/command
DIO4	4	Data/command
EOI	5	End or identity
DAV	6	Data valid
NRFD	7	Not read for data
NDAC	8	Not data accepted
IFC	9	Interface clear
SRQ	10	Service request
ATN	11	Attention
Shield	12	Cable shield
DIO5	13	Data/command
DIO6	14	Data/command
DIO7	15	Data/command
DIO8	16	Data/command
REN	17	Remote enable
Ground ...