Siemens sentron pac3200 conect

If the PAC3200 has a pulse output or a RS485 Modbus output, then you can connect this to the D105.

https://support.smart-maic.com/en/knowledge-bases/2/articles/154-d105-connecting-any-meter-with-an-impulse-output

https://support.smart-maic.com/en/knowledge-bases/2/articles/1038-d105-in-modbus-server-mode

There is no way to import your data into the system, sorry.

If I have tree device with RS485 Modbus output must I have tree D105 or only one ?

and ......If I use D105 in pulse mode where I can find the optical detection? I don't find it in your shop.
I would like to track my gas consumption

I attacment photo of my gas meter

If I have tree device with RS485 Modbus

https://support.smart-maic.com/en/knowledge-bases/2/articles/1038-d105-in-modbus-server-mode

where I can find the optical detection?

We do not have optical sensors, sorry.

If you find one, perhaps it can be connected to the D105 pulse input.
Tell us about it.

I would like to track my gas consumption

Gas consumption can be taken by impulses.
The only question is how to implement a pulse output for your gas meter.

https://support.smart-maic.com/en/knowledge-bases/2/articles/60-readings-from-gas-meter

photo of my gas meter

Check with your gas meter supplier about the pulse output option.
I’m not sure that you can read impulses from a digital meter using a reed switch, unfortunately.