Mass interconnect for VXIbus systems - VMEbus Extensions for Instrumentation - Technical

Hewlett-Packard Journal, April, 1992 by Calvin L. Erickson

Is short lead length between the VXIbus modules and the ICA connector important? If so, the HP E3720A may be the best choice.

Do most of the ICA wires (at least 60 to 75 percent) connect to VXIbus modules directly in a single mainframe? If so, the HP E3720A may be the best choice. If there are many wires that connect elsewhere in the system, the HP 9420A could be a better choice.

Are the limitations of the HP E3722A hinged ICA acceptable? A practical limitation in density is imposed by the requirement that all wires must bend every time the ICA is hinged down. Because the hinge is at the bottom, all wires must be tied at that point. This impedes wiring that must connect to resources above the VXIbus mainframe.

5. The fifth step is to refine the system layout and interconnect list. In particular, add detail on the layout of connector blocks in the ICA, including pinout definitions for each block. It is usually a good idea to retain a generic functional grouping. In other words, dedicate some blocks to sources, some to sensors, some to power, some to high frequency, some to switching networks, and some for growth. This functional grouping is particularly important for systems that will be testing many different DUTs. Remember that many of the custom connections can be made inside the ITA.

6. Finally, it is time to compile a list of all parts and products. For the system side, this should include the ICA, interface terminal modules (for the E3720A), ICA connector blocks and blanks, cable assemblies, and contacts. For the DUT side, this should include ITAS, ITA connector blocks and blanks, cable assemblies, contacts, and all parts necessary to customize the ITA for a particular DUT.

Conclusion

The integration of mass interconnect into a test system adds significant, but often essential, complexity. The system integrator is required to consider many factors. These factors include DUT quantity and type, signal characteristics and density, system components, available rack space, diagnostics, reconfiguration, and so on. One of the most important factors is the availability of appropriate mass interconnect products. The HP 75000 system resource interface provides an excellent set of tools for use with VXIbus-based test systems. Appropriate use of these products can greatly influence system cost, development time, and performance.

Acknowledgments

I would like to thank the following people for their key roles. At HP's Advanced Manufacturing Systems Operation, Mike Stefanisko for his technical expertise and advice, Dan Meitus and Jim McGillivary for their support. At MacPanel Company, Troy Rector and Kellie Coble for their responsiveness. At HP's Loveland Instrument Division, Charlie Schmidt for the design of the ITM, and in particular, Bryan Thompson for his involvement in the definition and in the details of introducing these new products.