<< Click to Display Table of Contents >> Navigation:  Project Module > Project parameters (detailed description) > General tab > Symbol handling > Main symbols without index (index empty)

This project parameter determines how a main symbol where the index attribute is empty should be interpreted.

 

 

There are two options available:

 

•Case_1 (Interpreted as main symbol)

•Case_2 (Interpreted as help symbol)

 

Case_1 is recommended in most cases. Main symbols are then interpreted as just main symbols, while help symbols in the same manner are interpreted as help symbols. No attribute values affect that. This is simple, straight forward and the outcome is easy to predict.

 

Case_2 should primarily be seen as a legacy feature, dedicated mainly to making life easier for users of old versions where Case_2 has been used. The idea behind Case_2 is that it may be beneficial in some situations, if main symbols in a simple way can “transform to” and be interpreted as help symbols. The amount of necessary symbols can then be reduced to some extent, since graphically similar symbols, which only difference is that one is a main symbol and the other one a help symbol, no longer are needed. This is where Case_2 comes in handy. If Case_2 is activated, all main symbols where the index attribute is left empty will act as help symbols. In order for symbols to work well in both these roles, they should preferably be defined as main symbols with cross-reference attributes. The cross-reference attribute will be used when a main symbol transforms to a help symbol.

 

Please note here, that Case_2 does not interact perfectly with the features that are described in the Help symbols with index topic, where indexes in help symbols are used to define additional devices or devices that are not even part of the circuit diagram yet. Some limitations will apply if you combine those two features. The reason is obvious. A symbol that becomes a help symbol because the index attribute is empty, can not have a value in the index attribute at the same time! Either the index attribute is empty, or it is not! So, a main symbol that is used as a help symbol, can not perform the trick that a genuine help symbol can, to define a device.

 

The conclusion of all this is that it in most cases, it is preferable to use ”actual help symbols” instead of the somewhat "indecisive" combined symbols of Case_2. To create a help symbol that looks exactly as an existing main symbol, except the fact that it is a help symbol, is easy and quickly done with the aid of the Symbol Generator. Roughly, you insert the main symbol, choose Symbol generator/Edit to change the name and change it to a help symbol. You add the cross-reference attribute, and end by choosing Symbol generator/Save. Please refer to the Symbol Generator sub-topic of the Drawing Environment topic.

 

In very old version of cadett ELSA/MG-CAD (version 4.2 and earlier), there were also a third and fourth case (Case_3 and Case_4). They were discontinued in 1998. There are no plans of re-establishing them.