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  • Question on schematic symbol

    My first venture into building a simple pcb using Altium. I am just making a schematic symbol for an led. The led is a plain superflux red diode. My question is when making the symbols what is good practice? I used 4 pins. designator is the pin number, Name is A1 reflecting Anode 1. So, for the pins I used 1,2,3,4 as designators. Name is A1,A2,C1,C2 for cathode, anode. This is a dip 4 package so the pins need to go some where......I simply drew a line attaching them all in parallel and wanted to see if when compiling this very basic circuit I would get errors. I am getting hundreds of duplicate net names and duplicate component designators. This was more simple with a two pin led...lol I attached some screenshots. Maybe I just forgot something here. Thank you in advance.

    Best regards,
    Adam

  • #2
    Well, Have a look in the datasheet to know exactly what connections there are!
    best practice in my opinion is:
    1) If datasheet has reference schematic symbol, use it! just rebuild it all in your library.
    2) If reference symbol is missing/you want to change it, make sure you ALWAYS include all of the solderable pins, even ones with are NOT internally connected.
    3) In your symbol, make sure you include key features, like in the diode you made- if part as two pair of connections, and they are internally shorted - draw it.
    4) Do not pack too many features in your symbol, it might become a pain to look at the schematic later on.
    5) Make sure each pin has its own, unique, designator- and that it will match precisely with the correct footprint pad designator.
    6) about pin names- Altium supports same pin names(not designators) for different pins, but it might be a better practice to give each pin a unique name too(GND1, GND2, DGND1, DGND2...) in case the schematic will be exported to a different CAD which does not suport this feature.

    Look at this example:
    Click image for larger version

Name:	Mosftet SCH Example.PNG
Views:	91
Size:	240.4 KB
ID:	12149
    In this case, we are given a shematic symbol reference within the package! nice

    So, we can see that there are multiple pins shorted on the inside- so, the schematic symbol will be as follows:
    Click image for larger version

Name:	MOSFET EXAMPLE SCH A.PNG
Views:	66
Size:	1.9 KB
ID:	12150
    As you can see, i kept is simple on the symbol- i did not add name as gate, source, or drain; pin naming and degisnators as follows-
    Click image for larger version

Name:	MOSFET EXAMPLE SCH B.PNG
Views:	61
Size:	6.3 KB
ID:	12151
    (moved it to make it visible, i kept the component small) - three points to make here:
    1) all the numbers on the outside, are the pin designators and have to be unique to the pin, in every component. meaning: more advances, if you have component with multiple parts, you still need to have unique pin designators.
    2) as you can see- on the left i gave each pin a unique pin name, it is preferable if you are planning to upload your work to the public- where people can download your work and import it to their own CAD.
    and on the right- i gave each pin the same name- this is what i usually do, (less clutter), since i keep all my work within my office, here everyone uses altium.

    NOTICE how in every pin, you have 4 little dots. make sure that those dots are on the outside of the component, it is the snapping point of different nets to those pins.

    hope this answers all of your questions regarding Schematic library editing in altium

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    • #3
      awhite I do not see reference designators for that diodes - fix that first and it can help. Did you specify in the library designator as "D?"

      Comment


      • #4
        Hi,

        I would use the default symbol for a Led, because it makes for a cleaner schematic. you can double the pins onto eachother so it looks like one pin but in fact are multpile.
        If you hide the designator the image look clean, when you attach a wire to it, it will give a small blue ball on it indicating there are multiple pins on it.

        Comment


        • #5
          I guess I am missing something. Reference designator is set as D? Pins are set as Pin1, Pin2, Pin3, Pin4, and named as C1,A1,C2,A2. I am not really sure what why that would be incorrect? My errors when compiling Pcbproject are Duplicate Component Designators. Clearly I am missing something but everything worked as I took the altium essentials class. I have no clue what I could have done wrong. The pins wont change, the device is the same component there is just 80 of them per board??....

          Comment


          • #6
            OOOOhhhhhhhhhhhh........................Sorry guys...I didnt annotate. What a dumb mistake. Problem solved

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