Memory layout(from version V254 onwards)

The configuration defines the view of the channel onto the memory and, thus, its logical structuring. The entire memory is structured as an array of 24 bytes blocks (union of the types of all contents). When defining each variable, the start position is specified by specifying the block index in this array.

A VE variable (also VE array) is saved continuously from the specified start position. If it is larger than a 24-byte grid, the following memory area (grid) must also be used. Basically, it is also possible to place several logical variables at the identical memory location, i.e. it is possible to enable several views onto a memory location. The NC does not monitor whether the individual variables overlap.

If individual variables are placed in memory, a non-used memory area per memory grid is left over, depending on the size of the variable. This unused area is no more addressable.