Introduction
All Spice engines differ in their implementation and details which is why it will be necessary to adjust designs that worked perfectly using Pulsonix Spice if they are to be simulated using PulsonixSim.
The biggest issue is that the way the respective parsers evaluate attributes for components differs significantly between the two simulator engines. This is generally the biggest issue to be addressed.
Passives
Fortunately, passive components such as resistors and capacitors do not need to be updated, but inductors might. Active devices will almost certainly need change.
Probes
A further difference is the way output is achieved. With PulsonixSim, every probe will generate a graph in a new window, the exception being where Inserted Graphs are now used as well as normal probes. Random Probes are also used in the same way as before once simulation has been run. These are single valued so no differential plots are currently available for these. Also, although support is planned, currently no digital output is available, so a digital to analog bridge will need to be inserted before any probe intended for digital signals.
Component Attributes
The following is a list of what differences to consider:
<Spice Device> - In both cases this is a single letter which defines the Spice category of the Part.
<Spice Value> - This is used to define the name of the model or subcircuit to be used for the simulation. With PulsonixSim this is strictly observed, but note that Pulsonix Spice sometimes used this field for parameters, notably with sources, so this may need to be checked and corrected.
<Spice Parameters> - This is the ONLY field used for parameters within PulsonixSim. Note that the specific parameters required for default models can vary slightly between the different simulator engines. Apart from a few specific cases, in general only the parameter values are required, not the names, but the order is important.
Spice Category - This is the same for both simulators and is used to categorise Parts when viewed in the Part Browser.
Spice Note - This is a new attribute which is used by some PulsonixSim Parts. It is intended to give extra information about the simulation behaviour.
Net Names
Your design must have a 0V net within it. Valid net names for this are ‘0’, ‘0V’ or ‘GND’ but Ground is not acceptable.
Elsewhere, all other net names are acceptable. Be aware that when net names are passed to the simulator, that name will then appear in the results, meaning that if it is not a user defined name, so $0022 may well appear in the plot results as N0022 etc., for example. (The ’$” is a reserved character in the simulator so ‘N’ is used as a substitute character.)
General Notes
Where a design which worked in Pulsonix Spice fails in PulsonixSim, it’s vital to refer to the simulation log file which can be accessed through the Simulation menu and Simulation Files, View Simulation Log File. The error messages in this are generated by the Spice engine and can be often cryptic, but will usually give at least a broad indication of where to look for the problem. Viewing the netlist from the same menu location can also be helpful.
Related Topics
PulsonixSim Overview | Part Browser | Inserted Graphs | Random Probe