from the Automation List department...
VME - what is it?
Information resources, documentation. topic
Posted by Dave Cooke on 23 May, 2000 - 5:07 pm

What's your understanding of the term - 'VME System' ?



Posted by Thomas Schuetze on 24 May, 2000 - 8:01 am
Hi Mr. Cooke,

a VME system is a bus system for industrial applications.
Components that might communicate via VME bus are e.g.: Power supply, computer, sensors, actuators and other automation components.

The operating DC voltages of a VME bus are 5.2V, +12V and -12V.
In addition to these 'power'- lines, there are 3 signal lines: ACFAIL, PG (means power good)and SYSRESET.

I'm not sure if other signals are defined for VME. As a manufacturer of power supplies, these are the ones important to us.

Hope I could help you, for more information please send mail.



Posted by Ralph G. McDonald, P.E. on 24 May, 2000 - 11:50 am
The VME bus is an industrial computer bus for control and instrumentation. Somewhat pricy but in my experience with high quality boards:

for a very good FAQ see:

Ralph McDonald

Posted by Murry Shohat on 24 May, 2000 - 2:02 pm
VME means Versa Module Europe. You can find out all about this long-in-the-tooth (since 1981) computer interconnect structure at It is one of the oldest modern standards and it remains a viable platform for industrial computing
thanks to the active membership of the ANSI-certified VITA group.

Murry Shohat

Murry Shohat Executive Director
Embedded Linux Consortium
3760 Cross Creek Road, Santa Rosa, CA 95403
Voice: 707.576.0111 FAX: 707.576.1944

Posted by holtek on 24 May, 2000 - 2:17 pm
Read the FAQ, man. there is a VMEbus FAQ located at
VME supposedly stands for "Versamodule Eurobus" or something like that. It is based on the eurobus form factor and includes a passive backplane for concurrent 16, 32, and 64 bit
communications between up to 21 cards on a rack. Basically, VMEbus is useful to us automation types as a reasonably safe way of getting different manufacturer's proprietary stuff to talk to each other. For example, you can buy the VMEbus version of an Allen-Bradley PLC5 and have it talk to an Interbus-S I/O scanner card. Theoretically, anything that plugs into VMEbus can talk to anything else on VMEbus. It ain't cheap but it works. CompactPCI was supposed to replace VMEbus in automation applications, but
we're still waiting for the parts to materialize. Hope this answers your question!

Jerry Holzer
R&D Electrical Engineer
Curt G. Joa, Inc - Boynton Beach, FL


DISCLAIMER: The contents of this message may not be consistent with the views or policies of my employer, Curt G. Joa, Inc.

Posted by Tony Firth on 24 May, 2000 - 4:12 pm
D. Cooke,

There may be other acronyms VME, but in the Process Control Computer field it stands for "Versa Module Europeen" which is a computer bus originally designed by Motorola over 20 years ago. It did not fly in the US but was picked up by
Motorola's German office where it was repackaged into a European format, that in turn became very popular there and was subsequently exported back to the US. The VME Spec covers the Bus Signals, connectors, pinout, card dimensions, etc. CPU cards, I/O cards, Motion Control cards, Etc. for "VME" are now available from very many vendors.
Hope this helps.

Tony Firth, Electrical Eng.,
Quester Technology Inc., Fremont,CA

Posted by Murry Shohat on 26 May, 2000 - 2:17 pm
Mr. Firth's answer is not accurate. Although VME was created by Motorola technical employees in Germany in 1980, it was launched as an open standard in the U.S. in 1981 by a coalition of companies -- notably Philips/Signetics, Mostek, Thomson and, of course, Motorola. I was one member of a small army of launchers and, for the next 16 years, I worked as an employee or consultant for leading VMEbus vendors.

Early success for VME came from both Europe and North America, but the U.S. quickly zoomed to marketshare leadership. The VMEbus International Trade Association, formed in the Phoenix area in 1984, instantly represented the VMEbus standard. Originally, VITA operated as a standards organization under IEEE jurisdiction. The group shifted to ANSI in June, 1993 and its operation as a standards organization is called VSO for VME Standards Organization.

From the beginning, the VMEbus was based on the established Eurocard format with its 96-pin DIN connectors. There was no repackaging as Mr. Firth claims.

Most of this info is available at the VITA web site,, at the bottom of the FAQ page.

Thanks for an opportunity for a journalist to be accurate for once... (smiles)


Murry Shohat Executive Director
Embedded Linux Consortium
3760 Cross Creek Road, Santa Rosa, CA 95403
Voice: 707.576.0111 FAX: 707.576.1944

Posted by Michael Klothe on 25 May, 2000 - 11:05 am
VME = Virtual Machine Environment. It's an operating system for ICL Series-39 mainframes. "VME" is also used casually to mean VME Bus which is a hardware standard.

If you'd care to visit the URL below you will find a fuller definition of VME and kindred VME-containing terms.

Michael E. Klothe
Detroit, USA

Posted by Rufus on 25 May, 2000 - 11:43 am
A VME System is simply a computer system composed of boards plugged into a VME backplane. Usually some pretty high performance stuff.

Contrast to PCI, PC/104, STD bus, Multibus, etc.


Posted by SimTech on 18 December, 2000 - 7:37 pm
With regard to Flight Simulation VME has been extensively used to increase throughput. Basically one healthy host computer pages DMA to the VME buckets to update the algorythms for their own dedicated arena. One VME chassis may be weather radar, one avionics bus, sound, etc. There are almost limitless specialized plug in modules available. From scientific measurement to high density I/O it seems to be a low cost high performance option to producing specialized I/O systems. Soon to go the way of the wire wheel in favor of Power PC alternatives.

Posted by Clay Crenwelge on 10 January, 2001 - 1:36 pm
Versa Module Eurocard (the most common definition) It is a non-propriatory computer bus standard that facilitates forward and backward compatability and multi-processing (1-21 processors). The bus uses async daisy chain, master/slave architecture and it is fast. It is the most common bus in the world and is usually used for industrial/military level applications.

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