Delta AH500 series, Hardware Operation Manual

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6. Supporting IEC 61131-3

The AH500 series CPU module supports IEC 61131-3.

The programming languages which are supported are ladder diagrams (LD), sequential function
charts (SFC), function block diagrams (FBD) and structured texts (ST).

Users can select a programming language according to their preference and the convenience. The
programming languages support one another so that the programs written by different users are
related.
7. Strong function block

Not only the standard IEC61131-3 function blocks are supported, but also the convenient function
blocks provided by Delta Electronics, Inc. are supported. Users can write the program frequently
executed in a function block so that the program becomes more structured and can be executed more
conveniently.

The symbol for a function block in a ladder diagram is like an Integrated circuit (IC) in a circuit diagram.
Owing to the fact that the ladder diagram is based on the traditional circuit diagram, the operation of a
function block is quite similar to the function of an integrated circuit. Users only need to send the signal
to the corresponding input of the function block, and they can receive the signal or state which is
required. During the whole process, users do not need to consider the processing procedure inside
the function block.