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3.5 Setting Up and Solving Circuit Equations 237
IgnoreMissingGround
IgnoreMissingGround is an option needed for analyzing pure control circuits (also known as block
diagrams). Equation setup for control circuits is based on the modified nodal analysis functionality
for electrical circuits, which are expected to contain a ground node. CircuitEquations displays an
error message when you try to set up equations from a netlist in which no reference to the ground
node is present. As pure control networks do not have ground nodes, these error messages must be
suppressed by means of the IgnoreMissingGround option, which allows the following values:
False
True
display a warning when no ground node is present
ignore missing ground node when analyzing control
circuits
Values for the IgnoreMissingGround option.
You do not need to set IgnoreMissingGround −> True when a ground node is present in a
circuit containing both electrical and control components.
IndependentVariable
With IndependentVariable −> var, you can specify a variable other than time as independent
variable for transient analysis.
Note that in Analog Insydes, transient analysis does not necessarily mean analysis in the time
domain. You can perform transient analysis, i.e. solving differential-algebraic equations, with respect
to any other independent variable, for instance, temperature. This feature is useful for tasks such
as parametric analyses or sizing problems with differential-algebraic constraints. Possible values for
the IndependentVariable option are:
Automatic
symbol
use value of option TimeVariable as independent variable
for transient analysis
use symbol as independent variable for transient analysis
Values for the IndependentVariable option.
If AnalysisMode −> Transient, then time-dependent variables or derivatives of circuit variables
with respect to time or other quantities are handled as follows.