Common Errors - Grounds!
ERROR -- Node xxxxx is floating

Perhaps the biggest problem to any new user (and, an amazing number of experienced users!) is the requirement that EVERY simulation have a single net used as a ground, and that net has to be named 0 (zero)!  The way PSpice (and every SPICE) works, it needs to have a reference node from which all other voltages will be calculated.  Also, every node in the design needs a DC path to that ground.

First Error - Wrong Ground
After learning that all designs need a ground, the new user's first mistake is using the wrong ground.  When you select Place Ground, you get an assortment of different ground symbols to use, and most new users assume you can use any of them!  That is wrong,the symbol you NEED to use is 0/source, that is, the 0 symbol from the source.olb library.  If you don't have the source library listed, you will need to add it to your available libraries list.  Select Add Library in the Place Ground dialog, and browse to the ...PSpice/source.olb and Add it to your list.

Alternately, you can double-click the node name on the symbol you have already put down, and change it to 0.  Since a power or ground symbol only functions to name the net they are attached to, this gives the ground net the correct name.

Second Error - Isolated Node
Another common error is having an isolated floating node, one with no DC path to ground.  This is usually caused, either by having series capacitors or more often, when you have placed a part with either no model associated, or that has unmodeled pins.  The usual correction is to place a large value resistor across one or more of the capacitors, or directly to ground.  Values from 1MEG to 1G are usually appropriate.








Third Error - Ground connected to a port
This error can catch even experienced designers unawares.  The purpose of the ground and power symbols is to name a net, but if you use a port or off page connector, they ALSO name the net they are connected to.  If you make the mistake of connecting a ground symbol direrctly to a port symbol, then the port symbol takes priority in Capture.  You can suddenly find your entire design is floating, and can take a while to isolate.  If you need to connect a port to ground, put a 0 volt voltage source between the two nets.  Advanced users often create a custom part that they use to place between equivalent nets.