Am I mixing up addresses and registers?

[TeXiCiTy]

I thought I figured out the address vs registers counting but now I am confused again with mbserver 0.5.0

I get these bits on the modbus RTU bus:
[Rx]: 0B 04 11 95 00 0A 65 B7
[Tx]: 0B 04 14 00 16 00 17 00 18 00 0F 00 00 00 0A 00 02 00 0A 00 0B 00 0C 20 42

Which translates to:
[Rx]: From slave 11 use function code 04 to read address 4501 with 10 values
[Tx]: Reponding to slave 11 call with 20 bytes:
22
23
24
15
...

So I would say address 4501 maps to value 22 at register 304502?
But in the dataview address 304502 maps to values 22.
Shouldn't the column name be "Register" instead of "Address"?

I think I'm just missing the "Modbus (0-based)" option for Modbus adr. notation.
"IEC61131 (0-based)" is in line with my expectation, but has the %IW4501 notation instead of the 304501 I expected.
I guess I should just learn to accept the IEC61131 notation which is clearer than just mixing 0-based and 1-based :)

[serhmarch]

Hello.

This is a frequently asked question. Users often get confused with old Modicon notation (from 1980s), which always starts with 1 (300001 address translated to register offset 00 00 in Modbus packet).

IEC61131-3 standard is modern notation which is slighty different (IW means Input Word aka Analog Input).

[TeXiCiTy]

Would it be a good idea to add "Modicon 0-based (legacy/deprecated)" to the "Modbus adr. notation" dropdown menu? Unfortunately a lot of modern appliances still use their 80s textbooks when writing their documentation.
If the option is red-colored it might make people aware they shouldn't use it for future development.

I asked Copilot which notation it assumed when asking about modbus address 304301 and it replied with Modicon because of the 3xxxxx notation. Even a flagship AI is silently using Modicon in the background :'(

[serhmarch]

Would it be a good idea to add "Modicon 0-based (legacy/deprecated)" ...

No, I don't think so. I've worked with Schneider PLC (which bought Modicon a long ago) a lot and something like 400000 or 300000 was always a mistake. So if for some vendors 400000 or 300000 addresses for their devices are valid it is bad.

I don't want other users to get confused when they realize that register 400001 is the address of the second register, not the first.