Help~~~~~~PSPICE:ERROR -- Node N00028 is floating ERROR

[tongtongsd]

Hi there:
I am a starter of Pspice, and I am running a simulation by pspice, but it keeps popping up error message.
I 've tried to connect a ground in the circuit, and place a huge resistor between the circuit and the ground, but it didn't help. Could any 1 check it out and see what's wrong here? Any help will be so appreciated!!


Kind regards
Adam


Following links is The curcuit schematic and error message:
**broken link removed**
**broken link removed**
**broken link removed**


The error message:

-----------------------------------------------------------------

**** 04/16/10 08:58:55 *********** Evaluation PSpice (Nov 1999) **************

** Profile: "SCHEMATIC1-Oringnal" [ D:\Data\PSpice\work\raji-schematic1-oringnal.sim ]


**** CIRCUIT DESCRIPTION


******************************************************************************




** Creating circuit file "raji-schematic1-oringnal.sim.cir"
** WARNING: THIS AUTOMATICALLY GENERATED FILE MAY BE OVERWRITTEN BY SUBSEQUENT SIMULATIONS

*Libraries:
* Local Libraries :
* From [PSPICE NETLIST] section of pspiceev.ini file:
.lib "nom.lib"

*Analysis directives:
.AC DEC 100 1 100MEG
.PROBE
.INC "raji-SCHEMATIC1.net"


**** INCLUDING raji-SCHEMATIC1.net ****
* source RAJI
V_Vin N00031 0 DC 0Vdc AC 1Vac
R_Rn N00028 N00025 12.5k
R_Rc2 N00040 N00034 12.5k
R_Rc1 N00034 N00031 100M
R_Rc3 0 N00040 100M
R_Rs 0 N00031 80
C_Cn1 N00025 N00034 4.8nF
C_Cn2 N00040 N00028 4.8nF
C_Cm1 N00034 N00031 9.6nF
C_Cm2 0 N00040 9.6nF
C_Cs 0 N00031 20pF

**** RESUMING raji-schematic1-oringnal.sim.cir ****
.INC "raji-SCHEMATIC1.als"



**** INCLUDING raji-SCHEMATIC1.als ****
.ALIASES
V_Vin Vin(+=N00031 -=0 )
R_Rn Rn(1=N00028 2=N00025 )
R_Rc2 Rc2(1=N00040 2=N00034 )
R_Rc1 Rc1(1=N00034 2=N00031 )
R_Rc3 Rc3(1=0 2=N00040 )
R_Rs Rs(1=0 2=N00031 )
C_Cn1 Cn1(1=N00025 2=N00034 )
C_Cn2 Cn2(1=N00040 2=N00028 )
C_Cm1 Cm1(1=N00034 2=N00031 )
C_Cm2 Cm2(1=0 2=N00040 )
C_Cs Cs(1=0 2=N00031 )
.ENDALIASES

**** RESUMING raji-schematic1-oringnal.sim.cir ****
.END

ERROR -- Node N00028 is floating
ERROR -- Node N00025 is floating


---------------------------------------------------------------------------------------------

 

[JoannesPaulus]

PSPICE does not like nets that do not have a DC path to ground. Add a 1Mohm resistor from N00028 to ground and from N00025 to ground:

R_Rn0 N00028 0 1M
R_Rn1 N00025 0 1M

and you should be fine.

 

[tongtongsd]

PSPICE does not like nets that do not have a DC path to ground. Add a 1Mohm resistor from N00028 to ground and from N00025 to ground:

R_Rn0 N00028 0 1M
R_Rn1 N00025 0 1M

and you should be fine.

Thx it works!
thanks so much!!!!!!!!!!!!!!!!!!

Added after 17 minutes:

PSPICE does not like nets that do not have a DC path to ground. Add a 1Mohm resistor from N00028 to ground and from N00025 to ground:

R_Rn0 N00028 0 1M
R_Rn1 N00025 0 1M

and you should be fine.

I changed my circuit as what you told me , and here is my new schematic
**broken link removed**

and I ran the simulation successfully.

now, I've got a question: Will this resistor and ground cause any change to the voltage or other characters of the circuit?

Thx !

 

[JoannesPaulus]

The resistor you added is much bigger than the impedance at that node so it won't change the behavior of the circuit. You do not need to add these resistor in a real testboard!

 

[flatulent]

What happened is that all SPICE simulators dislike nodes with no DC path to ground.

 

[tongtongsd]

The resistor you added is much bigger than the impedance at that node so it won't change the behavior of the circuit. You do not need to add these resistor in a real testboard!

Thx
BUt how could I put them on background?

 

[keith1200rs]

You don't need both resistors, just one of them. I don't think you can hide them, but you could avoid them altogether by combining the two series capacitors into one.

If you read the Spice manual, .options GMIN=xxx should fix it but in my experience it never does - I don't know why!

Keith.