Experimental Physics and
Industrial Control System

"Luchini, Kristi" <[email protected]> · Mon, 7 Jun 2004 02:52:37 -0700

Hi Ron,

IN the new Wiener crates we place the transition modules in the back of the crates. However,
since this is not possible in the older VME crates, just use one of the available slots
in the crate. I belive there is an empty slot next to the cpu in the BIC. 
If the crate is full after installing the transition modules, make sure that 
cooling in the crates is sufficient.   Ask John Dusatko or someone in hw to check 
this out for you. I imagine that cooling will be sufficient as the VME crate 
used for the BIC application is now in a cooled rack environment.

- Kristi

-----Original Message-----
From: Chestnut, Ronald P.
To: [email protected]
Sent: 6/4/2004 3:41 PM
Subject: Question on transition modules

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