Before PNS，some settings should be ready：

firstly，make sure that the power/ground nets exist，if not，please load upf file，a typical upf file is shown as below:

 

After loading upf， the power/ground  nets are  still not exist yet，because upf is only a guide for pns, so the following command is needed next :

derive_pg_connection -create_net  ;   ## create nets : DVDD  DGND

then use [ get_nets DVDD ] to make sure the DVDD is not  of  signal  type ( Power net & Ground net can only be get  by  [get_net DVDD -all ] )

 

 

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