Setting IO Addresses in the Hardware Declaration File - References - SIMATIC AX - AX Hardware Engineering documentation - Hardware Engineering,

An address can be assigned to a module in the hardware declaration using the IoConfiguration option.

The following example shows a PLC module (PLC_1) with an input (DI_1) and output module (DQ_1):

• The address for the DI_1 module is set to 9.0 and
• The outputs of the DQ_1 module is set to be available from the address 32

{
  "Devices": [
    {
      "Name": "Device1",
      "Modules": [
        {
          "Name": "PLC_1",
          "TypeIdentifier": {
            "OrderNumber": "6ES7 516-3AN01-0AB0",
            "Version": "V2.9"
          },
          "AccessProtection": {
            "AccessLevel": "NoAccess"
          }
        },
        {
          "Name": "DI_1",
          "TypeIdentifier": {
            "OrderNumber": "6ES7 521-1BL00-0AB0",
            "Version": "V2.2"
          },
          "IoConfiguration": {
            "InputAddress": "9.0"
          }
        },
        {
          "Name": "DQ_1",
          "TypeIdentifier": {
            "OrderNumber": "6ES7 522-1BL01-0AB0",
            "Version": "V1.1"
          },
          "IoConfiguration": {
            "OutputAddress": "32"
          }
        }
      ]
    }
  ]
}

For both the input and the output address, the configured value represents the "start address", i.e. the address at which the module's address space starts.

The length of the address space depends on the type of the module being specified in the hardware declaration. After running apax hwc compile, the length can be seen in the IO Address Lock File.

Note that both the InputAddress and OutputAddress options are of type string. The address can be specified in two formats:

• Either as a plain number (e.g. 32) where the number represents the byte address of the module, or
• In the notation <BYTE>.<BIT> where <BYTE> represents the byte address of the module and <BIT> specifies the index of the bit within that byte. Thus, the address values 32 and 32.0 are equivalent.
• The absolute bit-address is computed from the address using the formula (BYTE * 8) + BIT. For example 1.3 is the 11th ((1 * 8) + 3) bit.