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VXI - VMEbus eXtensions for Instrumentation #117685 08/18/20 09:20 AM
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Edstrom Offline OP
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This is a thread to save information and progress about VXI and related topics.

VXI is a huge topic as it is aimed at instrumentation, test automation and to some extent control applications, where the UI normally resides on a PC or workstation over a highspeed link like the MXIbus. Commands are standardized in text but sent from the pc/workstation application. There is chance a VME board could also host a UI but the crate at hand is a C sized as opposed to B size for VME. VXI adds a twice the depth C card size and a three connector D card size (also twice the depth) and defines row A and C of the P2 connector and optionally the P3 connector. More can be read here for instance: https://physics.bgu.ac.il/COURSES/SignalNoise/vxi_tutorial.pdf

The crate at hand has 5 Tektronix VX4287 32-Channel Differential Analog/Digital Input Module boards and 1 National Instruments VXI-MXI-2 Mainframe Extender which connects the crate to a PC, but I lack both cable and the apropriate PCI card so can't hook it up.

The VX4287 has 32 programmable analog/digital inputs with +/- 25 v range and down to 12.5 mV resolution and can be programmed per I/O. A couple of Zilog Super8:s per board takes care of the intelligance, firmware sits in external ROMs.

The VXI-MXI-2 board has no general purpose CPU but a couple of ASICs developed by National Intruments for which I lack docuemtation. They are referred to as TIC , MITE and MANTIS ASICs

EDIT: Found some info on the TIC here in Appendix A linked from here: vxitrig.htm WBM seems to have a lot of VXI goodies

The purpose of the project is not to make a fully functional system as it involves real world simulation that we don't have and high speed data links which we can't handle yet. Instead I think it would be of interest to get the text interface up and mocking the MXI interface or even the whole mainfram extender as it lacks a CPU, with a terminal. It would also archive the VXI firmwares involved and the system.

[Linked Image from i.imgur.com] [Linked Image from i.imgur.com]

Last edited by Edstrom; 08/18/20 10:22 AM.
Re: VXI - VMEbus eXtensions for Instrumentation [Re: Edstrom] #117688 08/18/20 03:38 PM
Joined: Aug 2015
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Edstrom Offline OP
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The crate in which these VXI boards resides was a part of the MSG weather satellite project at Saab Ericsson Space and was donated to the Chalmers University and auctioned at their annual ETA event, stripped from all application software unfortunately.

A small sticker gave me enough hints to Google it down to this video though: The Meteosat Second Generation

I would think that the crate was used only in development or through the launch as the satellite is still operational. 160 high speed I/O points are pretty impressive for 25 years ago!


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