From Measurement Systems and Sensors


8.1.1 Parallel Interfaces

Parallel transfer of digital data (including measurement data) offers much higher data rates than serial data transfer. Two factors contribute to this transfer step-up. One is simultaneous transfer of information in the form of 4-bit (in Centronics standard) to 32-bit (in VXI standard) words. The other factor refers to the fact that parallel data transfer avoids some routines necessary in serial transfer, such as error check and correction procedures used in dividing the bit stream into words [1, 2]. Parallel interface can be used in measurement systems arranged within a limited area (10 m 2 to 100 m 2, typically). Larger areas involve longer multiwire (at least 24-wire) cables, which is disadvantageous for cost-effectiveness reasons, and additionally involves some technical problems due to the RLC parameters of such cable, and its wave properties at transfer rates in the order of 100 KBps or more. Parallel transfer can be carried out through wired channel only.

There are several parallel interface standards, the dominant one being ANSI/IEEE-488 (ANSI is the acronym for American National Standard Institute). Developed by Hewlett-Packard under the name of HPIB (Hewlett-Packard Interface Bus), IEEE-488 is also known as IEC-625 (international standard). The generic name of IEEE-488 is GPIB (General Purpose Interface Bus). IEEE-488 is the first interface standard developed exclusively for measurement systems. The IEEE-488 interface is designed to interconnect measurement system components such as digital instruments, other electronic devices (e.g., generators, power supply units, and...

Products & Services
Bus Extenders
Bus extenders are used to increase cable lengths for distance-limited bus protocols.
Nut Runner Controllers
Nut runner controllers are matched with nut runners in precision fastening and assembly applications in which torque control is important. Both electric and pneumatic devices are available.
GPIB Controllers and GPIB Interface Boards
GPIB controllers and GPIB interface boards are devices that enable communications between GPIB buses and GPIB networks.
GPIB Products
GPIB products is a general search form for controllers, converters, extenders, expanders, isolators, switches and other products that use the general-purpose interface bus (GPIB). More detailed search forms are available for each type of GPIB product.
GPIB Converters
GPIB converters translate data from the GPIB bus to another bus type, and vice versa. For instance, an RS232-to-GPIB converter translates serial commands generated by the RS232 interface into GPIB commands.

Topics of Interest

9.1 CAMAC SYSTEM 9.1.1 Crate and Modular Measurement Systems: An Overview The highest measurement data rates are provided by crate and modular measurement systems with parallel interface. In crate...

Hewlett Packard designed the original bus in the 1960's. It was later accepted as a standard in 1978 by IEEE/ANSI as IEEE-488. At the time, it was revolutionary, allowing many convenient applications.

AD Analog Devices Company A/D Analog-to-digital conversion ADC Analog-to-digital converter ARQ Automatic Repeat reQuest ASK Amplitude Shift Keying B-ISDN Broadband Integrated Services...

REFERENCES [8.1] Coates, T. Interfacing to the Interface: Practical Considerations Beyond the Scope of IEEE Standard 488, presented at WESCON Conference, Session 3, September, 1975. [8.2] Fluke,...

Bus Strip Example: A multi-tap bus strip is a series of IEEE-488 recepticals (4 to8) wired in parallel that is...