How to use the MOUNTED attribute of Schematic Symbols.
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andyfierman 8 months ago
This post is to help people to understand what the MOUNTED attribute - associated with each Schematic Symbol placed into a Schematic - is for. The MOUNTED attribute is a **Bill of Materials (BoM)** attribute. * It is not a **PCB** attribute. It is used to indicate if a component is to be mounted on the PCB *when it is assembled*. To illustrate by example, suppose it is required to design a PCB with a microcontroller that is in-circuit programmed for the prototype PCBs but in production, the micro is to be supplied pre-programmed by the manufacturer. The prototype PCBs will need a programming header connector and may need another connector for debugging purposes but the production PCBs do not need them fitted. * The point here is that the prototype and the production boards *are built using exactly the same PCB*. They both have the same PCB footrpints and tracks on them. They just have different parts fitted according to the Bill of Materials (BoM). So for the prototype PCBs, the BoM is run with the MOUNTED attribute for all the parts including the programming and debug headers set to `Yes` but for the production PCB, the BoM is re-run with the MOUNTED attribute for these two headers changed to `No`. It does not make sense to interpret the MOUNTED attribute as a **PCB** attribute because that would imply that a PCB with the MOUNTED attribute for all the parts set to `Yes` would be made with PCB footprints and tracking for all the mounted parts whilst a PCB made with the MOUNTED attribute for some of parts set to `No` will be made with those PCB footprints and associated tracking, not present. * Therefore changing the MOUNTED attribute like this would generate two *different* PCBs. That does not make sense because these are in fact, two different PCB projects not one with two stages in its lifecycle simply indicated by the status of the MOUNTED attribute in the BoM.
FrankCA 2017-09-25 00:25:39
Thanks for clarifying this Andy.
w4mmp 2018-03-20 01:37:32
Hello, Thanks for the explanation.  But I still have a question.   How do I indicate on the schematic that a part attaches to the PCB but is not mounted on the PCB?  Parts such as panel mount switches and such?
LISA_DALTON 2018-03-20 06:12:40
[w4mm]( I think the best way to handle that would be to put text on the schematic. If you wanted something on the PCB, You could maybe add a symbol of some sort, like an asterisk or whatever you might choose right where the component would be covering it (or wires) right where it would be somewhat or completely covered. I however had not had an instance where this is even necessary. If someone else is building your boards, just give them a list of what is not to be mounted if it is not already obvious. -Lisa D
andyfierman 2018-03-20 06:29:38
@w4mmp, To understand more about what elements should be included in the schematic and how to represent them, please see (2), (4), (5) and (6) in: [https://easyeda\.com/andyfierman/Welcome\_to\_EasyEDA\-31e1288f882e49e582699b8eb7fe9b1f](
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