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sinara-hw / DIOT_Backplane

DIOT backplane fork
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Backplane Mechanical Issues #2

Open gravelpitman opened 1 month ago

gravelpitman commented 1 month ago

Incorrect mounting hole spacing

image

Crate dictates a hole spacing of 122,1 as shown above

image

Hole spacing in PCB shown above.

The difference of 0.4mm is too big in my opinion.

Placement of the coordinate system

BackplaneOrgin

This placement does not make sense. In my opinion, the location of the coordinate system should be in the mounting hole, for example, in the lower left mounting hole. This location provides any possibility to calculate the correct location of connectors, (16,6mm between modules and backplane orgin i Y axis)

Not using meaningful units of measurement (mm)

image

Please use max 0,01mm incremenst (thousandths of a millimeter)

Guideline for creating revisions

-Correct holes placement

image Please make them as shown above.

-TOP connectors

image Every dimension measured between the connector orgin and PCB orgin

-TOP Guides

image Guide X axis orgin same as mounting holes Every dimension measured between the guide orgin and PCB orgin

-BOTTOM connectors

image Every dimension measured between the connector orgin and PCB orgin

-BOTTOM Guides

image Every dimension measured between the guide orgin and PCB orgin

The assumptions I made regarding crate assembley

  1. Modules inserted symmetrically image The picture shows symmetrical clearance in the X axis of the entire crate and symmetrical clearance i Y axis of crate

  2. Maximum Misalignment of AMPHENOL 51940-650 according to the manufacturer's designation (datasheet: https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/bus-20-067.pdf , 13/24)

filipswit commented 1 month ago

@gravelpitman can you verify mechanics?

DIOT_Backplane_v1([No Variations]).zip

gravelpitman commented 1 month ago

@filipswit Now placement of connectors is correct. My only complain is the positioning of the top and bottom edges in relation to the PCB orgin. image Please move only edges of PCB.

filipswit commented 1 month ago

Corrected edges placement.

jordens commented 2 weeks ago

Also, the 7 Würth terminals (not mounted) are not on a grid. Could they be snapped to a 30 mm or to a 6 HP grid?

jordens commented 2 weeks ago

The backplane mounting hole centerline separation appears to be inconsistent with other sources.

I'm not sure whether the CAD models of the chassis rails and walls are the authoritative reference here.

The "classic" 3U crate certainly has the centerlines at 122.5 mm, not 122.1 as in the cad models.

image

Then there are these drawings which also use 122.5 mm:

https://schroff.nvent.com/sites/g/files/hdkjer281/files/acquiadam_assets/2021-04/33007-649-51_assy.pdf?asset_type=Drawing%20Document

image image

https://schroff.nvent.com/sites/g/files/hdkjer281/files/acquiadam_assets/2021-06/63972-333.pdf?asset_type=Installation%20Manual%20/%20Instruction%20Sheet

image

And https://www.hartmann-electronic.com/download/b213r06040/?wpdmdl=33416&refresh=67322eff6cf311731342079

image