DNP vs. DNL

[robotix3]

Do you prefer DNP or DNL for schematics (Do-not-populate vs. Do-not-load)? This is used when you want the option of adding a component later but do not want the assembler to add the component.

[Fgrir]

I've always used "open" or "DNI" (do not install), or whatever else the customer specifies.  Never really had any assembly problems with using any english words that imply that the part shouldn't be there, but to be safe I usually make sure there is nothing in the BOM to tell them what parts would go in those spots.  They can't install them if they don't know what they should be...

[ejeffrey]

I don't like to just leave it off the BOM.  You would still have a footprint with a designator, and it would still show up in the centroid file.  So if you drop it from the BOM it looks like something is missing.  Listing it as DNP or whatever in the BOM makes it perfectly clear that you want the part omitted.

[aandrew]

While we're discussing this, I'd like to know how people declare this in Altium. I know Altium has ECO tags you can use, and it also has variants, but both seem... off.

back in the SDT/PCB386+ days I just prefixed a component's value with '*' (e.g. *10k) and made an appropriate note in the drawing/assembly files. I can still do this, but there must be better ways.

[amyk]

I've seen NS (No Stuff) and DY too --- the latter, often encountered on Asian schematics, still mystifies me as to its origin.

[T3sl4co1l]

While we're discussing this, I'd like to know how people declare this in Altium. I know Altium has ECO tags you can use, and it also has variants, but both seem... off.

back in the SDT/PCB386+ days I just prefixed a component's value with '*' (e.g. *10k) and made an appropriate note in the drawing/assembly files. I can still do this, but there must be better ways.

I do two ways:
1. Set a field to DNP, typically Comment, Value, Description or MFGPN.  Null or delete unused parameters (e.g., no MFG).  Better not to enter a default value (that is, if you mean to specify a value---IF it were to be placed---as a default), in case the assembler takes that as instruction to place a part there instead.
2. Use Assembly Variants.  This is what it's there for, of course!  Use the schematic Compiled View tabs to graphically inspect, set and modify alternates, or set them from the variant dialog.  Make sure the OutJob is set to use variants, and that at least the BOM uses the variant (but preferably all outputs, so you capture parts placement, and yes even 3D view, with the variant).

Nice part about variants is you can set non-component footprints to DNP, and include them on the BOM as such, so there is no question about what should go where.  Often, assemblers will ask about so-and-so, like, should we place anything on FID1, FID2 etc.? -- obviously not, you might say, because those are fiducials, graphical features -- but they ask to make sure, and specifying as such in the BOM answers that question immediately.

Heh... well... the better assemblers ask, I suppose a cheaper one might just go ahead and assume what you meant.  All the more reason to be as specific as possible.

Tim

[TiN]

Also DNI, NO STUFF, OPT, /X

[phase90]

I have been using DNL for a couple decades.  I am not sure how I first encountered and started using it.  I imagine the parlance came from *loading* the chip shooters with reels, so that was what was used by those I learned from at the time.  I leave the line in the BOM with the quantity listed as DNL.  That way if it populated in the future, the line is there (I group components by type - resistor, cap, inductor, discretes, ICs, connetors, hardware, etc, so adding a new line puts it at the end of the list, which I do not want).

[Someone]

NF
No Fit
Seems there are more options to use for this than symbols for capacitors.

[WorldPowerLabs]

I generally use "DNP" in the part number field of the BOM and I write out, "DO NOT POPULATE" in the description... because some of our contract manufacturers are, well... let me just say that they've contacted me with questions about "missing parts" that are actually DNP.