aca500plus + aca1233n measurements for enclosure

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  • Hi,

    I'm designing a 3D printed enclosure for these devices. Can you confirm the measurements I've come up with with my sub-par calipers? In particular I want to make sure the desk to aca1233n clearance is correct so that it is properly supported. I think it should be 8.85mm if I've measured everything correctly.



  • Hi,

    while the body of the CPU connector may measure 8.7mm, you should give it 9mm, because the frame for the pins has tolerances that ultimately results in the connector not always being mounted flush to the board.

    The ACA500plus stands 13mm above the table, not 14.

    For the distance from the front of the ACA500plus PCB to the CPU slot connector, I'd give 71mm, as it's not a good idea to push the A1200 accelerator all the way in. This moves your other dimensions 0.5mm further back.

    Your ?? dimenstion can be calculated: With the connector being 9mm and the board inserted exactly at the middle, it's 4.5mm above the ACA1232/1233 board. The position relative to the ACA500plus height is "-0.8mm", and the board thickness of the A1200 accelerator is also 1.6mm. This results in your ?? dimension to be 7.7mm.

  • Awesome, thank you for the info. When I set the ACA500plus to desk distance to 13mm, I do indeed measure a distance in CAD of 7.7mm to the ACA1233n. However, I am consistently measuring 14mm from the bottom of the standoffs to the ACA500plus board. Perhaps the standoffs are too long or the plexiglass under the CF card a bit too thick? Do you think it would be better to compensate with 8.7mm to the 1233n or remove the standoffs and have the ACA500plus supported at 13mm? Granted the back end of the 1233n dropping 1mm is probably not a huge deal.

  • Depending on the rubber feet under the A500 - which may very well be different on different-year models - there may be variations.

    When I chose the stand-offs for the X-Surf-500, I had to calculate the height and find the right stand-off myself. In detail:

    The standoff under the plexi is exactly 8mm. The plexi itself is 1.6mm. The CF-card slots are 4mm, including soldering/measuring tolerance (drawing shows 3.8mm, but I guess that the component floats a bit higher during reflow soldering). This results in 13.6mm calculated, but if you measure with a caliper on the tightened stand-off, you get to 13.3mm. Since the circuit board can always flex a little without risking any damage, 13mm is the *much* better choice over 14mm. I have actually attempted 14mm stand-offs for the X-Surf-500, but that results in horrible flexing of the card; my guess is that hardly anyone would accept that.

    So if you really want to be exact (as in "probably close to the maximum precision that the material can be handled"), then assuming a height of 8mm for the ACA12xx would be best. Your main trouble will always be the rubber feet of the A500, as they vary in height.