Funktsiooniblokid

Funktsiooniblokid, often translated as function blocks, are a fundamental concept in IEC 61131-3, the international standard for programming languages used in programmable logic controllers (PLCs). They represent reusable software components that encapsulate a specific set of operations and data. Unlike simple functions, function blocks maintain internal state, meaning they can remember values between calls. This state is typically stored in internal variables.

Function blocks are defined with an interface that specifies the inputs and outputs. Inputs are used to pass data into the block for processing, while outputs are used to return the results of the operations. Some function blocks also have in-out parameters, which allow data to be passed in, modified, and then passed back out. This ability to retain state and manage data flow makes function blocks powerful tools for building complex control systems.

They are used to implement a wide range of functionalities, from basic logic operations like timers and counters to more complex algorithms for process control and motion management. The reusability of function blocks promotes modular programming, making it easier to develop, debug, and maintain PLC applications. Developers can create custom function blocks tailored to specific industry needs or application requirements, further enhancing the flexibility and efficiency of PLC programming. Standard libraries provided by PLC manufacturers often include a comprehensive set of pre-defined function blocks for common tasks.