Using a KNX server like eibd with PHP in combination, you might come to a point where you want to convert the DPT/EIS encoded telegram values to decimal format.

For some data types, it works by simply using PHP hexbin(), but it does not for 2-byte floating point values.

In many forum threads the following sample is used:

 

 
BUT it converts negative values wrong! This can lead to e.g. wrong temperature values which might affect the heating control.

Use this snippet instead:

Reference

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