Working people make mistakes, some people do never make mistakes!
I work to live, my boss thinks I live to work!

I´m not programming that long but i have seen a lot of different way's to convert a flowchart to a program in a plc. Sometime it is easy to read but takes a lot of the internal cpu (e.g. some graphical tools like Graph from Siemens or Hitachi). A big disadvantage of these programs is that you need these tools to be installed on your pc with the source code. If you don’t have the source code than your F*ucked.
I prefer to use the and/or logic that is in almost every plc on the market (confirm the IEC 61131–3 standard. (Source: TwinCAT Quick Start 2.8) ). Even in some robots (i've seen it in the Motoman robots) there is a little compiler that can be programmed with this language.

The most functions i've seen are special made for that company, mostly not useable for anything else. I've made a standard for myself with universal and easy functions that can be common used. Thanks for all who have helped me with some functions.
I've divided the function in the folowing groups:

• Step
  Functions to convert an flowchart to a plc program. With function blocks.
• Fast step
  Functions to convert an flowchart to a plc program.
  A very fast methode! (aprox. 25 STL instructions per cyclus!)
• IO
Functions to read inputs and write outputs or a combination of it.
• Timer using SFC64
Functions using the internal clock function SFC64 "TIME_TCK"
• DB
Functions to handle DataBlocks (only for step7^® Plc!)
• Mathematical
Functions to calculate a mathematic function.
• Mathematical
Functions for making (easy) mathemetical calculations. (Most likely as example for own functions).
• XY axis
Functions for axis movements on PLC's

You can download all functions as a library (step7 v5.3). Or as STL source in the separate pages.