Netlist error message ? New to Multisim - Student edition 11.0

[rzolnowski]

------ Checking SPICE netlist for Design1 - Wednesday, June 01, 2011, 5:42:58 PM ------
SPICE Netlist Error in schematic RefDes 'u1', element 'xu2':  Invalid subckt definition name 'regulator5v'
SPICE Netlist Error in schematic RefDes 'u1', element '<unknown>':  Due to errors, the subckt instance 'xu2' has been omitted from the simulation
======= SPICE Netlist check completed, 2 error(s), 0 warning(s) =======

I made a new component using a subcircuit with an LM7805T and three capacitors.  I get the above message when I use the component but it seems to be working fine.  Why?

[Tien_P]

Hi,

Below is a link to the Multisim component creation tutorial, have a look at it if you have not seen it before.

http://zone.ni.com/devzone/cda/tut/p/id/3173

The error messages indicate you made a mistake when you creating this comonent, post the circuit so that I can see what you did.  I looked through the model and it should work in Multisim.

[rzolnowski]

Tien,

Thank you for your time and help.  I did follow the tutorial several times.  None of the efforts helped.  So I did some more reading and finally got it to "work" but don't understand why I am getting this error.  Here are the attachments:

Design! - circuit that I wanted to make a component of.  Not complex, just trying to learn how to do it

5vRegulator1A - initial netlist with the LM device renamed

Then I read some more and somewhere it was recommended to remove all connections from the components, generate the netlist, and then edit the netlist to make the pins correct.

5vRegulator was created by leaving the components unconnected.

The netlist in my original email was when I moved the capacitators down into the subcircuit definition.  This seemed to get rid of all errors except the one in my original posting.  As I indicated, the multimeter attached to the output with 12v on the input is generating 5.xx v...which is correct.

[Tien_P · Accepted solution]

Hi,

All SPICE model must begin with a ".model" or a ".subckt" statement.  A components that use a .model are called 'core models' and they include parts like diode, pnp, npn MOS.  A model that starts with a .subckt is like a black box that has other parts inside such as resistors, capacitors, voltage sources, math equation, core models or other .subckt model. To turn your Circuit 1 to a SPICE model, you must add a .subckt statement and finish the model with an .ends statement. 

A .subckt statement has three components, the first is the .subckt to tell the SPICE the type of model, next is the model name and finally the number of nodes in the model. To create a model from a circuit in Multisim, using your circuit I added junctions so that you can see the model nodes and in Multisim do the follow.

 

1.  Select Transfer>>Export Netlist and save the file 

2.  Open the netlist file you created in step 1 with Notepad

3.  Go to the first line and type:

.subckt Mymodel Line Ground Out

4.  Scroll to the last line and type:

.ends

5.  You now have a complete model that you can create a component from

Your file "5vRegulator1A" is a circuit netlist that you can simulate using the transient analysis, AC analysis et... When you use the circuit netlist to create a component, it is an incomplete model and that's why you got the error.

[rzolnowski]

Tien,

Worked like a charm!  Thank you for taking your time to help me out.  Multisim is a great product.

Richard