DRC does not catch missing nets

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ElektroLuke
Posts: 6
Joined: 07 Aug 2019, 03:25

DRC does not catch missing nets

#1 Post by ElektroLuke » 07 Aug 2019, 03:46

When layouting a PCB in diptrace, it is very easy to accidentally remove a net. When one means to unroute a trace, but presses delete as one intuitively does, it deletes the net. (AFAIK there is no hotkey for "unroute" though one can be set manually, I've set shift-X to unroute segment which is a workaround)

DRC does not catch this missing net. Connection check does not catch this either. I think they compare with board netlist, so the net is not there because it was deleted. Deleted in error, but still gone.

The schematic has the net, so all seems fine if you check there, but isn't. One would need to renew from schematic before running a connection check to find this, otherwise all the checks tell you all is well while the PCB you just designed is missing a net, which can be a costly mistake if you find out after having boards fabricated.

It would be nice if DRC caught this (maybe if it compares with schematic netlist?).

Also if the "delete" button unrouted the trace without removing the net, this problem would not occur. (What is the use-case for removing nets during PCB lay-outing? Only time I used it was accidental. Does anyone use this or might it be better if removing nets was only possible in the schematic editor? Would that break anyone's workflow or rather save a lot of hassle with accidental mistakes?)

Alex
Technical Support
Posts: 3129
Joined: 14 Jun 2010, 06:43

Re: DRC does not catch missing nets

#2 Post by Alex » 08 Aug 2019, 09:18

You can activate "Route -> Lock Net structure" to never delete nets by accident. After activation, delete button will remove the trace but keep the net.
DRC doesn't search missed nets. But you can run "Verification -> Compare to Schematic", this function does exactly what you need.

ElektroLuke
Posts: 6
Joined: 07 Aug 2019, 03:25

Re: DRC does not catch missing nets

#3 Post by ElektroLuke » 20 Aug 2019, 02:45

Thanks, good to know about "Lock Net Structure". (I only wonder why it is not locked by default?)

Alex
Technical Support
Posts: 3129
Joined: 14 Jun 2010, 06:43

Re: DRC does not catch missing nets

#4 Post by Alex » 20 Aug 2019, 09:09

Some users design simple boards without related schematic. Activated "Lock Net Structure" doesn't allow to create and change any net in PCB Layout therefore the feature is turned off by default.

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