4 Replies Latest reply on Jul 18, 2012 8:35 AM by brian.schubert

    Simulator Settings Resistances (Zero/Load/Infinite)


      While playing around with simulations I am struggling to understand how the values for Zero, Load, and Infinite resistance are chosen and used by the simulator.


      First of all the Simulator Settings in the System Preference menu.


      Where and how are these values used during a simulation? 

      They seem to directly affect an LC (Qualitative) simulation more so than a DC (Numeric) simulation.  Although, I have seen diodes crash the SPICE simulation if the ZERO Resistance value is set too low here.


      Second, where do the default values for ZERO, LOAD, and INFINITE come from for ARCs?

      ARC Resistance.JPG

      It is my guess that these are pulled from a Quatization Scheme but I am not positive. 

      If they are pulled from a Quatization Scheme is it possible to modify the default QScheme?




      Any insight would be greatly appreciated.




        • 1. Re: Simulator Settings Resistances (Zero/Load/Infinite)



          The settings for ZERO, LOAD and INFINITE are used for both LC and numeric analysis. These values represents the resistance value of an ARC  when the ARC represented as resistance arc.


          The diode representation of the ARC uses the PICE diode directly. Since the spice diode mode is highly non-linear, then in-proper setup the resistance value for the current loop will cause the singular matrix and cause the spice simulation error.


          the Quantization Scheme only define the threshold for certain operations. The zero, load and Infinite resistance are still from system preferences.


          Hope it helps.



          1 of 1 people found this helpful
          • 2. Re: Simulator Settings Resistances (Zero/Load/Infinite)

            Well then I guess I don't understand why I can't seem to change what the resistance values are when using a resistive ARCs default Zero, Load, or Infinite settings.



            Right now my System Preferences > Simulator Settings is set to...


            Zero Resistance = 0.000001


            Infinite Resistance = 1,000,000


            Load Resistance = 50



            However, when I use a model that simply has a resistive ARC (no SAINT code) and set the ARC to be Zero, Load, and Infinite.  When simulating in DC and taking the ARC.R property I find that the values for Zero, Inifite, and Load are respetively...


            Zero = 0.0001


            Infinite = 100,000,000


            Load = 5


            Where are these values coming from?

            • 3. Re: Simulator Settings Resistances (Zero/Load/Infinite)









              Sorry about confusions.


              The  definition of the mention enum variable is in the QSchemes. There is a default Qschemes defined in the RunTime.property files


              netsim.qscheme.default.current = /QuickStart/QSchemes/Enumeration/Current/switch_0A001_15A0


              netsim.qscheme.default.resistance = /QuickStart/QSchemes/Enumeration/Resistance/switch_0R0_10M0


              netsim.qscheme.default.voltage =


              So following the default Qscheme for resistance -> /QuickStart/QSchemes/Enumeration/Resistance/switch_0R0_10M0


              You would see all definitions:






              For ZERO  it is 1.0E-4 ( lower limit of band ZERO )

              For LOAD it is 5.0 ( lower limit of band MEDIUM )

              For INFINITE it is 9.999999999999997E7 ( lower limit of band INFINITE )




              If either QSCheme is not defined or default QScheme is absent, then the values are picked from System Preference.






              • 4. Re: Simulator Settings Resistances (Zero/Load/Infinite)

                It all makes sense to me now


                Thank you for your help.  This will be very useful.