Base address:

In the display menu you can select Base 0 or Base 1

Modbus Poll base 1

Display with PLC style addresses. Base 1.
This window shows 30 registers from 40001 to 40030. (Protocol address 0 to 29 using Modbus function 03 Holding registers)

Modbus Poll base 0

Display with protocol style addresses. Base 0.
This window shows 30 registers from 0 to 29. (Function 03 Holding registers)