Buffer endianness - Manual - SIMATIC AX - System.Serialization

By default, the buffer is interpreted as little-endian during deserialization (i.e. the smallest address stores the least significant byte of the value). In the example below, value = UINT#16#1235. As return value of the Deserialize function, nextValueOffset = start offset + value byte length = 0 + 2 = 2.

USING System.Serialization;

FUNCTION SerDe_Demo
    VAR_TEMP
        data : ARRAY[0..1] OF BYTE := [BYTE#16#35, BYTE#16#12];
        value : UINT;
        nextValueOffset : UDINT;
    END_VAR

    // value = 4661 (0x1235)
    // nextValueOffset = 2
    nextValueOffset := Deserialize(UDINT#0, data, value);
END_FUNCTION

The endianness can be specified/changed by passing an additional argument to the Deserialize function or by using the DeserializeLitte or DeserializeBig function, respectively:

USING System.Serialization;

FUNCTION SerDe_Demo
    VAR_TEMP
        data : ARRAY[0..1] OF BYTE := [BYTE#16#35, BYTE#16#12];
        value : UINT;
        nextValueOffset : INT;
    END_VAR

    // Deserialization using big endianness
    // value = 13586 (0x3512)
    // nextValueOffset = 2
    nextValueOffset := Deserialize(0, data, value, Endianness#Big);

    // Alternative for a deserialization using big endianness
    // value = 13586 (0x3512)
    // nextValueOffset = 2
    nextValueOffset := DeserializeBig(0, data, value);
END_FUNCTION

Buffer endianness - Manual - SIMATIC AX - System.Serialization - System.Serialization,

System.Serialization library