Can't find the node error

[DawnLord0]

I'm trying to find the problem node in my circuit. But I have no idea how to read the error list that multisim gives me. Can someone help me? This is what I keep getting.

Instrument operation performed   (2009, May 21, Thursday, 19:58:20)  
|   Instrument Analysis: Transient Analysis  
|   |   Plot title:
|   |   Analysis settings
|   |   |   Initial Conditions: Zero initial conditions  
|   |   |   Starting time (TSTART): 0
|   |   |   Stop time (TSTOP): 1e+030
|   |   |   Plotting increment (TSTEP): 0.001
|   |   |   Maximum time step (TMAX): 0.001  
|   |   Perform consistency check
|   |   Variables from analysis  
|   |   |   Show device values at the end of the simulation  
|   |   Representation as SPICE commands
|   |   |   begin-scope page
|   |   |   checknodes 3
|   |   |   save all
|   |   |   iplot all
|   |   |   set reltol = 0.01
|   |   |   set trtol = 7
|   |   |   set itl4 = 100 
|   |   |   set method = "gear"  
|   |   |   set ramptime = 0
|   |   |   set convlimit
|   |   |   set rshunt = 1e+009  
|   |   |   -param hrange 0 1e+030 
|   |   |   save
|   |   |   tran  -env-options 0.001 1e+030 0 0.001 zero_ic  
|   |   |   if-error end-scope audit-log-show
|   |   |   show all
|   |   |   showmod all  
|   |   |   end-scope
|   |   Custom Analysis Options  
|   |   |   Relative error tolerance: 0.01 
|   |   |   Truncation error overestimation factor: 7
|   |   |   Upper transient iteration limit: 100
|   |   |   Integration method: gear
|   |   |   Transient analysis supply ramping time: 0
|   |   |   Enable convergence assistance for code models
|   |   |   Shunt resistance from analog nodes to ground: 1e+009
|   Output from instrument analysis  
|   |   singular matrix:  check nodes adac1in:xu2.o0#branch_1_0 and adac1in:xu2.o0#branch_1_0 (How do I read this?)

|   |   singular matrix:  check nodes adac1in:xu2.o0#branch_1_0 and adac1in:xu2.o0#branch_1_0
|   |   singular matrix:  check nodes adac1in:xu2.o0#branch_1_0 and adac1in:xu2.o0#branch_1_0
|   |   singular matrix:  check nodes adac1in:xu2.o0#branch_1_0 and adac1in:xu2.o0#branch_1_0
|   |   singular matrix:  check nodes adac1in:xu2.o0#branch_1_0 and adac1in:xu2.o0#branch_1_0
|   |   singular matrix:  check nodes adac1in:xu2.o0#branch_1_0 and adac1in:xu2.o0#branch_1_0
|   |   singular matrix:  check nodes adac1in:xu2.o0#branch_1_0 and adac1in:xu2.o0#branch_1_0
|   |   singular matrix:  check nodes adac1in:xu2.o0#branch_1_0 and adac1in:xu2.o0#branch_1_0
|   |   singular matrix:  check nodes adac1in:xu2.o0#branch_1_0 and adac1in:xu2.o0#branch_1_0
|   |   TRAN:  Timestep too small; initial timepoint: trouble with (led_mod:xled1) d1:xled1  
|   |   doAnalyses: timestep too small 
|   |  
|   |  
|   |   tran simulation(s) aborted 
 

[_user32]

DawnLord0,

A singular matrix can arise for a few reasons - sometimes with floating nodes (internal to model or at circuit level) or with inductor components.   Is it possible to post the circuit in question?

adac1in:xu2.o0#branch_1_0

This line refers to an instrument or component connection on U2 (adac1in is likely internal to the model) - usually a #branch is a SPICE designation to force/analyze current going through a node (SPICE tries to calculate the current/voltage at each node at each time step), thus the error is stating that the Multisim SPICE engine cannot correctly calculate this in this part of the SPICE netlist.  I believe you are getting several errors because SPICE tries to automatically change the time stepping (in an attempt to solve for a solution based on SPICE engine settings) and will eventually stop if unsuccessful.

If we can analyze the circuit, we'll have a better idea what is going on.

Regards,

Patrick Noonan
Business Development Manager
National Instruments - Electronics Workbench Group
50 Market St. 1-A
S. Portland, ME 04106
Email: patrick.noonan@ni.com
Tel. (207) 892-9130
Fax. (207) 892-9508