The Future of GPIB

From time to time, you probably wonder how you will communicate with your test and measurement equipment in the future. Will you be able to connect to your GPIB instrument? Is LXI replacing GPIB? Does Hi-Speed USB offer better performance and faster setup time than LXI? What new instrument control interfaces are emerging? These are all critical questions for today’s engineers and scientists.

NI has a long history of working with instrument control interfaces. We have seen many instrument control bus technologies – with varying bus speeds, latency, connectors, cabling, and prices – come and go over the years. GPIB, however, has remained a de facto standard for PC-based control of stand-alone instruments and will continue to be used in test and measurement systems for many years to come.

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Figure 1. GPIB remains strong after 30 years.

“It just works,” is the top response from engineers and scientists when asked why they use GPIB for instrument control. In the engineering world of unknowns, it is reassuring to know you can count on your GPIB-based systems to function properly.

Despite the emergence every few years of new bus technologies for instrument control, GPIB remains the foundation for instrument control systems and serves as a critical bridging technology in applications using multiple instrument control bus options. NI has a long-standing commitment to the longevity of GPIB and the ultimate success of your instrument control applications.

What’s New in GPIB?

NI began developing GPIB products in 1976, driving the introduction of the ANSI/IEEE 488 standard, so engineers and scientists could control their instruments from desktop PCs regardless of vendor. Since then, NI has actively advanced the GPIB standard and GPIB technologies by gathering feedback from users and instrument vendors for all components required to use the bus – from integrated circuits and interface cards for multiple OS platforms to software firmware and application programming interfaces (APIs). These collaborative efforts during the past 30 years helped GPIB become a proven, easy-to-use control interface with the following benefits:

• More than 5,000 available GPIB instruments
• Software compatibility with other instrument interfaces (enabled by NI-VISA and SCPI)
• Proven ease of use and familiarity
• Low-latency performance (less than 100 µs, which is better than LXI and USB)
• Good bandwidth performance (up to 1.8 MB/s using IEEE 488 and up to 8 MB/s using HS488)
• Extremely rugged cabling and connectors
• Long-distance remote control via fiber-optic and Ethernet extenders

Moving forward, NI is continuing its strong commitment to GPIB and instrument control. In fact, during the past five years, we have redesigned many GPIB products to include new features, reduce physical size, and enhance capabilities. Some of these new GPIB products and research areas include the following:

• Introduction of the first PCI Express GPIB controller
• Hi-Speed USB-to-GPIB high-speed controller
• RoHS-compliant controllers, cables, and integrated circuits
• Windows Vista OS compatibility
• Mac OS X compatibility
• Solaris 9 and 10 compatibility

Software and Instrument Driver Updates

The success of GPIB and its continued use beyond the next decade is largely related to ubiquitous software and instrument driver availability. NI LabVIEW is an industry-standard software for developing instrument control applications, and the most recent LabVIEW release, Version 8.5, includes new instrument control features. A dedicated team of NI software engineers also develops new instrument drivers for instruments released by hundreds of different vendors. Today, the NI Instrument Driver Network offers more than 5,000 instrument drivers, and we have added more than 150 new drivers in the past three months.

In addition, we continue to see the GPIB interface heavily used in the industry today. In the third quarter of 2007, more than 80 percent of new instruments publicly announced by leading test and measurement companies incorporated a GPIB interface.

Finally, we continue to develop the GPIB device driver and frequently release OS support updates to ensure your success using GPIB with whichever OS and development language you choose. The latest software and instrument driver updates are listed below:

• LabVIEW 8.5 for Windows, Mac OS, and Linux® OSs
• LabVIEW SignalExpress for Windows
• NI Measurement & Automation Explorer Version 4.3
• NI 488.2 Version 2.5 for Windows including compatibility for Windows Vista
• NI 488.2 Version 2.4 for Sun Solaris including compatibility for Solaris 10
• NI-VISA Version 4.2 including compatibility for Windows Vista, Ardence Phar Lap ETS, and Wind River VxWorks

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Figure 2. GPIB continues to be a reliable option for instrument control.

New Instrument Control Bus Technologies

Despite the use of GPIB in the industry as a de facto instrument control bus interface for the past 30 years, it is important to remember that no single bus or technology has been able to deliver the best performance, simplest ease of use, and lowest cost. GPIB demonstrates the best combination of these elements but is not the best in all categories. Thus, you should understand the specific instrument control needs of your application before choosing an instrument control bus.

NI constantly evaluates the characteristics of new instrument control bus technologies to provide recommendations to our users and ensure interoperability with existing GPIB interfaces. Three new promising instrument control bus technologies are USB, Ethernet, and Cabled PCI Express. USB-controlled devices are well-suited for applications with portable measurements, laptop or desktop data logging, and in-vehicle data acquisition; however, cable length is limited to 5 m and the connectors are not rugged. Ethernet is most useful for creating a network of highly distributed instruments that require remote access capabilities across large geographies. Be aware that Ethernet has the highest (worst) latency of all instrument control bus interfaces. This can cause significant bottlenecks in high-performance applications. Cabled PCI Express is an emerging technology that holds promise for a high-bandwidth, low-latency interface for instrument control and data sharing in high-performance applications. However, it requires some cost for the controller and cables, similar to GPIB today.

In summary, GPIB remains a dominant industry standard for general-purpose instrument control and will continue meeting most engineers’ measurement and automation needs for many years to come. National Instruments is committed to supporting GPIB products, and we will continue its investment beyond the next decade. You can rely on NI to provide you with the information and products you need as instrument control options continue to evolve. Our efforts are continuing to focus on improving your instrument control experience while maintaining backward compatibility to protect the development investments you make today.

Watch this webcast to compare GPIB to other instrument control options.

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GPIB is platform independent but...
I just read your article about GPIB and am pleased to know that the technology is here to last. I am also very happy because GPIB is available on all major computer platforms, specifically also for the MacOS. However I would like to see even better support on this platform with USB GPIB and also support for high speed USB DAQ solutions à la NI-USB- 6251-BNC!
- Urs Lauterburg, University of Bern, Physics Institute. urs.lauterburg@space.unibe.ch - Feb 1, 2008

GPIB Cable
Your summary of the GPIB referencing the rugged cable and connectors brought to mind the 94 Earthquake. The only thing that saved our instruments was the fact that all were on the GPIB buss and several Fluke 45's were found hanging loose by the connector. A feature I'm sure was not recognized by the connector designer.
- wa6ogh@msn.com - Jan 29, 2008

It Just Works
I remember fighting with a Tek 6804 Scope. Kept debugging and debugging my code... Finally a visiting Tek FE offered that the Ethernet wouldn't support the speed of what I was doing and that I needed to "direct connect" using GPIB! Sure would have been nice if this had been documented... GPIB? It just works RIGHT!
- Jan 29, 2008