Function Block Diagram (FBD) Programming Tutorial - PLC Standard Function BlocksComparison Function BlocksSelection Function BlocksMake Your Own Function BlocksIn the standard from IEC a lot of function blocks are described. Here’s an overview of the most important blocks in the official FBD description most basic functionality of a PLC program is logic. Combined called combinatorial logic. Logic is the simplest form of algorithm that, via the states of its inputs can set some outputs. Basically, there are two different bit logic functions or operations in FBD. With just these two you can derive a whole bunch of other logic functions let’s s..See more on plcacademy[PDF] Logix 5000 Controllers Function Block Diagram Programming block diagram (FBD) programming language. This manual is one of a set of related manuals that show common procedures for programming and operating Logix 5000 controllers. For a complete list of common procedures manuals, refer to the . Logix 5000 Controllers Common Procedures Programming Manual , publication . 1756-PM001.