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Using the Motega software is very simple. You can enter data for tubes having multiple different sections (like an ECF80 which combines a triode and a pentode), and then Motega calculates a model and generates pSpice model files. There are however some guidelines for a correct functioning of the software when entering data, especially with tubes having multiple different sections. An example of such a tube is the EABC80:
![]() The main window
A picture of the main window is given below:![]() Specifying the number of different tube sections is easy, see the next examples:
The sections window
In the sections window you can specify the electrical behavior of each section:![]() When specifying the pins for a certain type of tube section, the number of pins selected in each edit field must equal the number of this type of tube section. Taking an ECC81 for example having its anodes connected to pins 1 and 6, you fill in a '1' and a '6' separated by one or more spaces. If pins are shared within a section, like the double diode in the EABC80 with both cathodes connected to pin 7, then this pinnumber is filled in twice (separated by one or more spaces). In the data panel you can specify sets of data which define the voltage-current relation of the selected section. The weight parameter is used in the optimization process and in fact shows how important this dataset is to you. If you have a dataset which is less important in the tube model (maybe screen grid current), then you can give it a lower weight than the default 1. By doing so, the model will better fit the other datasets. The rest of the data panel should speak for itself. Entering data
When entering data, it is best to use the following guidelines:
I don't have Ig2-data
Some datasheets do not provide data for Ig2. But you really must enter some data in order to enable Motega to calculate an Ig2-model that makes sense. Try to find the datasheet of a comparable tube, and make a rough educated guess for Ig2. Two curves of 4 points or so will do the job.
The optimization parameters window
Generally, the parameters in this window need not to be altered:![]() Normally, the selected option for the 'Initial generation' is optimal. If you however run the source files of Motega on your own Matlab version and you don't have a license for the Statistics Toolbox, then the 'Latin Hypercube Samples' functionality is not available and Motega will switch to the random initializing function. You may choose the random function manually to see how the resulting tube model performs. Calculating a model
Before calculating a model, you may want to check the entered data by selecting 'Check tube data' from the menu. To be on the safe side, also make sure that you saved your project before calculating a tube model.Calculating a tube model can take a minute, after which a window pops up like this one: ![]() For each tube section you can also select a plot which shows the specified data points with red circles, and the behavior of the tube model as a blue line: ![]() Generated output files
Several files are generated if the tube model optimization succeeds. First of all a pSpice model file is generated for the entire tube including all sections. The name of this file equals the type name of the tube. For each different tube section a file is generated also, and the type-character of the section is appended to the name of the file. In case of an EABC80 the files are:
Batch optimization
If many tube models must be calculated, then you really don't want to wait for each tube model to be finished and then have to load in another tube and start waiting over again while Motega is optimizing the model. You can however enter all tube data of several tubes and save the tube projects without calculating an optimized tube model (don't forget to select the 'Check tube data' option!), and then calculate all tube models in a single batch. Make sure all tube projects are saved and closed, then you are able to select the 'Batch optimizer' option from the menu. You will be prompted to select a folder, and the batch optimizer will then start to calculate tube models for all tube projects it finds in the specified folder. The progress is shown in a report window:![]() |