Addressing

For addressing a single value, use the following address format:

START_ADDRESS@DATA_TYPE, where START_ADDRESS indicates the area and the starting address of the element,
and DATA_TYPE – the data type

To address one of the bits of the word, you must use the following format:

START_ADDRESS.BIT_INDEX, where START_ADDRESS indicates the area and the starting address
of the element, 
and BIT_INDEX – the bit number in the 16-bit word (from 0 to 15)

An array of values can be set using the following address format:

START_ADDRESS[LENGTH]@DATA_TYPE, where START_ADDRESS specifies the area and the starting address
of the element, 
LENGTH – number of elements in the array, 
and DATA_TYPE – the data type

Note that zero-based addressing is used for all types of data areas. This means that the addresses entered by the user are not shifted by 1 when constructing a Modbus frame

The table below maps data areas to supported address ranges, data types and access modes.

Data Area	Address Range	Data Type	OPC UA Access Mode
Output Coils	0 - 65535	Boolean	Read/Write
Input Coils	100000 - 165535	Boolean	Read Only, Read/Write (in slave mode)
Internal Registers	300000 - 365535	Boolean, Byte, Word, Int, DWord, DInt, Float, Double, QWord, Long, String	Read Only, Read/Write (in slave mode)
Holding Registers	400000 - 465535	Boolean, Byte, Word, Int, DWord, DInt, Float, Double, QWord, Long, String	Read/Write

For byte data type you must specify the byte order in the word (MSB or LSB) after the @ character, for example: 400000@MSB

The following are examples of available addresses:

• 400020@INT

• 300001.14

• 300999@FLOAT

• 400005[10]INT

• 100035[12]

• 000021