Comparing schematic and PCB design

Discussion in 'General Electronics Chat' started by RG23, Jun 30, 2015.

  1. RG23

    Thread Starter Active Member

    Dec 6, 2010
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    I have multiple PCB files all related to the same schematic but not all are the same.
    How to confirm which PCB design is corresponding to the actual schematic?
     
  2. dl324

    Distinguished Member

    Mar 30, 2015
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    Do the boards and schematic have a revision number? They should...

    If no revision info on the board, visually inspect (I know it could be tedious) and compare differences.
     
  3. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    What PCB program ?
     
  4. RG23

    Thread Starter Active Member

    Dec 6, 2010
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    @what PCB program ?

    Its Altium schematic and pcb designer

    There is no revision number
     
  5. crutschow

    Expert

    Mar 14, 2008
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    Compare the boards to see if you can spot the physical differences in the layout or traces.
    You might want to print the layers on clear film so you can overlay them for ease of comparison.

    Once you spot the differences, then you should be able to determine which one corresponds to the schematic.
     
    RichardO likes this.
  6. JWHassler

    Member

    Sep 25, 2013
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    PCB layouts can be visibly different and yet still implement the same schematic.
    Look at the time-stamps of the PCB-files as a first cut.
     
  7. djsfantasi

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    Apr 11, 2010
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    As mentioned, PCB layouts can be visibly different, yet implement the same schematic. Take a look at these two PCB board designs. They are designed from the same schematic. (Ignore the strip in the second picture)
    [​IMG]
    [​IMG]
     
  8. ErnieM

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    Apr 24, 2011
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    Files will have a time and date of creation. Typically the most recent files the most current version.
     
  9. Roderick Young

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    Feb 22, 2015
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    One layout has a 4.7k SIP (resistor network in one package), and the other has separate 4.7k resistors. Check the schematic to see which one you want.
     
  10. pwdixon

    Member

    Oct 11, 2012
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    That was an example of the same schematic different layout, I don't think it was the circuit the OP was referring to.
     
  11. dl324

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    I would point out that there is no guarantee that the most recent version of the PCB file will correspond to the most recent version of the schematic file. Either could be revised independently. For example, in Eagle schematic changes can cause PCB routes to be removed; but I don't have to save the changed PCB. In that case, latest PCB does not correspond to latest schematic.
     
    Last edited: Jul 2, 2015
  12. nigelwright7557

    Senior Member

    May 10, 2008
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    I always put the filename of the pcb on the pcb so I don't get mixed up.
     
  13. cmartinez

    AAC Fanatic!

    Jan 17, 2007
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    I'd compare them using two simple approaches:
    1. Component match and quantity
    2. Number of nodes and matching interconnects
     
  14. Stuntman

    Active Member

    Mar 28, 2011
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    Can you find the project file? That should let you know which PCB files are associated with that schematic.

    If you wanted, you could make a new project, add the "correct" schematic file, then all the PCB files you think may be associated.

    Open the schematic, under the Design tab, you can update each of the PCB files with the schematic on hand. Depending on your settings, you should be prompted of all the changes without actually having to make them. The one with no changes (or simply adding rooms or other garbage) should be ready to roll.... or you may find one that can be easily modified to your needs.
     
  15. djsfantasi

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    Apr 11, 2010
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    Exactly. I was reinforcing @JWHassler's point. There is no expectation of a one to one relationship
     
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