Form factor
Bob
There has been some discussion about card form factor.
The first question is do we design around a backplane, a stackable
module form, or pick one module as the mainboard and plug everything
into that.
Eurocard has been one suggestion as a form factor. While I personally
love Eurocard, the boards and connectors are expensive.
Stackble connectors are a pain in assembly.
Backplanes are inherently evil at high speeds.
Plugging everything into one main board makes that a critical design
item and that much harder to upgrade.
Discuss. :)
Bob
bus. I don't know the official name of it, but there were many many
prototype cards and backplanes available for it in the day.
Yet another option would be to build these to fit in an existing
instrumentation chassis like the Tektronix 500/5000 series. That gives
you a predefined backplane, a form factor for cards, enclosures and
chassis available in several sizes with well regulated power supplies,
and perhaps additional audience.
bownes
But one of those as the primary enclosure with input boards and output boards that plug into a main board would be feasable if a tad expensive.
Some modules lend themselves to plugins on a main board (output modules for example) while things that need to chain like input modules ( think pre amp followed by prescaler followed by trigger sense) don't.
On Dec 21, 2010, at 1:29 AM, Chris Albertson <alberts...@gmail.com> wrote:
>>> Eurocard has been one suggestion as a form factor. While I personally
>>> love Eurocard, the boards and connectors are expensive.
>>>
>>> Stackble connectors are a pain in assembly.
>>>
>>> Backplanes are inherently evil at high speeds.
>>>
>>> Plugging everything into one main board makes that a critical design
>>> item and that much harder to upgrade.
>
> I agree with all of the above.
>
> I think what we want is simply a mechanical standard. Something that
> will simply hold everything in place.
>
> What if every module was in it's own metal box? Each box has a
> forward or "user facing" panel that is tall and narrow and contains
> things like input jacks and status LEDs and a rear facing panel that
> is for power and module to module interconnect. Many of the
> modules, I assume would work as stand alone gadgets (a trigger is a
> usful device all by it self) To assemble a system you place all the
> boxes like books on a shelf. Maybe even some book end so they don't
> fall over. But you might build a wood cabinet, put a handle on top
> and metal bumpers on the corners. The wood cabinet would house the
> modules and also the power supply and the rats nest of interconnect
> wiresSo those who like to be neat can make nice wood cases and the
> rest of us can have a working system made of a half dozen boxea and
> cales all over the work bench
>
> Here is an example of a module box
> http://www.hammondmfg.com/pdf/1455L1601.pdf
>
> We would not have to specify a height or length, only the width needs
> to be uniform. But in our case the width becomes height when you turn
> them on edge. Some modules might need two PCBs and a wider box. We
> should make a list of connectors to be used for power and so on for
> the rear pannel
>
> I had previously suggested about the same thing but only to make the
> box the same size as a disk drive so we could use common existing
> racks. I'd still prefer that but maybe these hammond boxes are more
> popular
>
>
> --
> =====
> Chris Albertson
> Redondo Beach, California
>
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