The following figure shows the connection definition in eCl@ss Advanced.

Connections are defined in FEATURE GROUP ADN293 (="CaX connection and function).

The device has 5 connections and 1 function group (see figure above). The function group is the container for the electrical functionality of the part and contains 2 functions in the given example.

According to this division 3D data and other properties of connections are defined in the sections AAQ672 (="Connection").

Information on connection logic, etc. are determined by the functions in the function group.

	Note
	Physical and logical connection properties are separated. This strict separation is not so strong in the CNS classification system.

The most important information of a representative connection for part 2964500 is shown in the figure. In addition to its 3D coordinates with connection direction (see framed data in the following figure), AAQ672 usually also contains information on the conductor material, cross-sections, its color and stripping lengths, etc. (In this case, classification was only carried out sparingly without this additional information)

	Note
	Connection identifier and position are mandatory.

Properties of connection: The key AAM650 defines connection position and direction according to ISO AXIS ID data type definition. The relation to logical connection properties is realized by connection identifier AAN337 (here ID = 3:1).

The connection identifier links physical and logical connection properties.^[52]

Connection identifiers of the five connections. All other data is hidden. (Above figure is representative for the other connection details omitted here).

In this case applies:

In this case the five connections are divided in two functions (see "Number of functions 2"):

Function group with two functions (expanded on first level). Note: eCl@ss is largely independent of languages (English and German function is both described by "AAQ676")

The relation between connection and function takes place within eCl@ss key AAQ678. Two connections belong to the first function and three connections to the second function. As an example we consider the respective function entry of Identifier "3:1".

Function group with two functions. Two connections (within AAQ678; not displayed here) belong to the first function (green frame). The second function contains three connections (red and blue box). The entries of identifier "3:1" are expanded in the red box. Note the large amount of date, which serves the "bookkeeping" to a great extent.

The previous considerations can be summarized as follows: (You can see the function number indirectly in the figure above)

Now that logical connections are linked to the physical connections, the question arises as to what the corresponding switching symbol of the entire device (a device with one function group and two functions) looks like. This is done within the eCl@ss key AAQ520.

	Note
	Here, we only consider the "Vanilla Case" without special wishes, etc. Special wishes can definitely also be used in eCl@ss within the scope of IEC symbols. However, they are open for interpretation and base on certain assumptions, which may vary between different target systems. For such cases general symbols are planned (state April 2019).

The component is therefore described from the combination of S00305 (="coil") and S00230 (=switch).

IEC symbol code via eCl@ss AAC338 (S00305 or S00230)

In summary:

	Note
	The table is structured in the same order as the eCl@ss document; if, for example, S00230||2|||2 were swapped with S00230||2|||3, this would result in an incorrect circuit diagram (this is less relevant for classification via PARTproject than for reading in eCl@ss Advanced)

On the CNS classification side, the Connection EclassSymbolMap feature shows a fairly compact formulation of the concept described.

Following figure shows the comparison of the logic from the table with the circuit from the datasheet.

Logic from table --- Circuit from datasheet (special wishes apparent)