Adressen in Modbus

Servus,

verwenden alle Modbus-Funktionen einen einzigen linearen Adressraum (0x0
– 0xFFFF) oder verfügen diese jeweils über einen eigenen Adressraum (0x0
– 0xFFFF)?

Ich stelle diese Frage wegen einer Tabelle aus diesem Link
http://www.modbustools.com/quickstart.asp

Device address MODBUS address Description Function R/W
1...10000 address - 1 Coils (outputs) 0 Read/Write
10001...20000 address - 10001 Discrete Inputs 01 Read
40001...50000 address - 40001 Holding Registers 03 Read/Write
30001...40000 address - 30001 Input Registers 04 Read

In Modbus Poll stehen zwei Adressen zur Verfügung: PLC Address und
Protocol Address.

PLC Addresses command (Display menu):

Use this command to display addresses starting from 40001 if e.g.
holding registers are displayed.
Base 1 is used for the address.

Protocol Addresses command (Display menu):

Use this command to display addresses as in the protocol request and
response.
Base 0 is used for the address.
This is convenient when testing the protocol of a slave device as
protocol addresses always starts from zero.

Kann mir jemand den Unterschied aufklären?

MfG
Senmeis