Experimental Physics and
Industrial Control System

"Chestnut, Ronald P." <[email protected]> · Fri, 4 Jun 2004 15:41:14 -0700

In our group at SLAC we are using some MV167/MV177 and some PPC 2700 VME controllers. Each class has its own transition module. Rumor has it that using the wrong transition module can damage the CPU. Since there seem to be active components on the transition module, this is entirely believable.

We also have some older VME crates with homebrew "transitions"; these crates all currently have MV167/MV177 modules. The interface is entirely passive, with connections to the backplane and to external connectors for one console port and ethernet. The advantage of these crates is that one can actually get modules in without a mallet, and that many are available. The layout of the crate precludes using the commercial 2700 transition module without moving the power supply around.

Before I fry an MV2700, I would like to know if this purely passive "transition" solution has the possibility of actually harming the CPU. Can anyone explain the caveats of these transition issues, please!

Thank you in advance.

/Ron Chestnut 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System