Saturday, September 17, 2016

Mapping Update

The Mapping dialog and associated documentation have been updated.
For details see
This information is also linked to the "Mapping" section of the System help.

Monday, September 5, 2016

STRING Functions

Today's FBDK2 auto-update contains IEC 61499 "Simple (REQ/CNF) FB" implementations of all the standard character string functions defined in IEC 61499, including implementations for both WSTRING (16-bit character strings) and STRING (8-bit character strings) types. WSTRING is implemented as a container for the Java String class, whose instances are immutable, and STRING is implemented as a wrapper for a mutable array of bytes. This gives the latter the following practical advantages:
  • Significantly less object creation and garbage collection overhead
  • Smaller (approaching 50%) payload sizes for PUBLISH/SUBSCRIBE and CLIENT/SERVER packets, with correspondingly smaller encode/decode times.
The tradeoff, of course, is that STRINGs can only represent 256 characters - usually the "C0 Controls and Basic Latin" (0000-007F) and "C1 Controls and Latin-1 Supplement" (0080-00FF) defined in ISO/IEC 10646. For a richer, multilingual character set, WSTRING with its attendant overhead costs must be used.

Documentation for these FB types can be found in the strings folder of the FBNavigator.