The ArbitraryCurve() function allows you to generate a curve from an arbitrary mathematical expression of node-voltage and branch-current waveforms. Additionally, the arbitrary mathematical expression can include built-in vector functions, which are all described in Function Reference.
The syntax of the ArbitraryCurve() function has the following syntax with the arguments explained in the table below:
ArbitraryCurve(vector_expression, vectors_to_keep, curve_name, graph_name, grid_index, axis_name, OPTIONAL_PARAMETER_STRING)
Argument | Description |
vector_expression | A mathematical expression of node-voltage and branch-current waveforms. This expression can include built-in vector functions. |
vectors_to_keep | A space-delimited list of vectors from the vector expression that the program produces in the .PRINT statements for each vector during SIMPLIS simulations and in the .KEEP statements during SIMetrix simulations. This ensures that the vectors supplied in vector expressions are available for plotting after the simulation is complete. |
curve_name | Name of the
curve as it appears in the report. Note: For your curve to
appear in the report, you must prefix the curve name with "DVM".
|
graph_name | Name of the graph for the new test report* |
grid_index | Grid on which to place the curve* |
axis_name | Axis on a particular grid* |
OPTIONAL_PARAMETER_STRING | A space-separated set of KEY=VALUE pairs that defines additional formatting parameters** |
* For additional information about graph_name, grid_index, and axis_name, see Graph Address System.
** For additional information about OPTIONAL_PARAMETER_STRING, see Optional Parameters.
Suppose a node out is the output of an op-amp and its voltage is plotted with a fixed probe on a graph named DVM Output.
The following call to the ArbitraryCurve() function will plot the slew rate of the op-amp output on a new grid above the default grid.
ArbitraryCurve(1u*diff(out), out, DVM Slew Rate, DVM Output, A2, slew rate, yUnits=V/us)
Suppose that, after a simulation run, you want to plot two vectors against each other in an X-Y plot. A simple example plots the forward current against the forward voltage of a MOSFET body diode.
The following call to the ArbitraryCurve() function will generate the XY plot on a new graph sheet named Forward Biased.
ArbitraryCurve(XY(-QDUT#D, #S - #D), QDUT#D #D #S, DVM SIMPLIS, Forward Biased, A1, vertical, xlabel=Body Diode Forward Voltage ylabel=Body Diode Forward Current)
The following syntax rules apply to the OPTIONAL_PARAMETER_STRING argument:
ylabel=Body Diode Forward Current Temp=-40In this case , the program would read this incorrectly as two optional parameters:
Spaces in values are allowed as long as no spaces are on either side of the equal sign. Thee three examples below illustrate this:
The following table lists the available formatting options for use in the OPTIONAL_PARAMETER_STRING argument.
Parameter Syntax | Value Type | Description |
xgrid=positive_integer | Any positive integer | Specifies space between the x gridlines |
ygrid=positive_integer | Any positive integer | Specifies space between the y gridlines |
xscale=lin | log | One of two options:
|
Specifies the units for the x axis |
yscale=lin | log |
O ne of two options:
|
Specifies the units for the y axis |
xlabel=string | Any alphanumeric string | Specifies a label for the x axis |
ylabel=string | Any alphanumeric string | Specifies a label for the y
axis The ArbitraryBodePlot()function ignores this option if curves are placed on multiple grids. |
xunits=string | Any alphanumeric string | Specifies the units label for the x axis |
yunits=string | Any alphanumeric string | Specifies the units label
for the y axis. The ArbitraryBodePlot() function ignores this option. |
xMinlimit=integer | Any positive or negative integer | Specifics the minimum x-axis limit |
xMaxlimit=integer | Any positive or negative integer | Specifics the maximum x-axis limit |
yMinlimit=integer | Any positive or negative integer | Specifics the minimum y-axis limit |
yMaxlimit=integer | Any positive or negative integer | Specifics the maximum y-axis limit |
showpoints=TRUE | FALSE | TRUE or FALSE | Specifies whether or not to show points on graph. |
color=color_specification | One of three options to
specify the color:
|
Specifies the color for the
curve. Note: See the next section for information on these three methods for specifying a color.. |
You have three options for specifying the color for a curve:
color=color_namewhere color_name is one of the 16 built-in color aliases as listed in the following table with the hexadecimal code.
Color Name Alias | Hex Code | |
Red | #FF0000 | |
Green | #008000 | |
Blue | #0000FF | |
Teal | #008080 | |
Purple | #800080 | |
Maroon | #800000 | |
Navy | #000080 | |
Black | #000000 | |
Magenta | #FF00FF | |
Lime | #00FF00 | |
Salmon | #FA8072 | |
Medium violet red | #C71585 | |
Brown | #A52A2A | |
Indigo | #4B0082 | |
Medium orchid | #BA55D3 | |
Blue violet | #8A2BE2 |
color=#rrggbbwhere rr, gg, and bb are hex numbers from 00 to FF.
You can specify any color for the curve by using a hexadecimal specification.
color=SEQ:nwhere n is a positive integer between 1 and 20.
SIMetrix has eight default curve colors, starting with red, green, blue, etc.
To change and extend these colors to a maximum of 20 user-defined curve colors, follow these steps:
The ArbitraryCurve() function is also available as a SIMetrix script function and can be called from a post-process or final-process script. Calling this function from a script is useful when you need to generate a large number of curves and/or if the length of the arguments makes the testplan difficult to read or edit.
SimplisDVMAdvancedUtilMeasurementArbitraryCurve(array, log_file)
Argument | Description |
array | A string array that contains the normal arguments to the CreateArbitraryCurve() function |
log_file | The DVM log file that is an argument passed into the post and final process scripts |
Example 1 above could be generated in a post-process script with the statement below:
Let return = SimplisDVMAdvancedUtilMeasurementArbitraryCurve([ '1u*diff(out)', 'out', 'DVM Slew Rate', 'DVM Output', 'A2', 'slew rate', 'yUnits=V/us' ], log_file)