Failing on "simple" Temperature chain setup from W1-GPIO sensors to Frontend/UI

(Openhabian 3.1.0 on RaspberryPi 3 Model B V1.2 1GB)

I just started with OH few days ago and now got stuck since days in bringing up a few temp values (including reading the docs). When trying to link/channel the sensor thing to an item, it gets red/ERROR:COMM. I use the Web-GUI mainly. My status/steps in detail : I added seven DS18B20 sensors to GPIO4 and see that all data and temperature is live and available in the file system:

openhabian@openhabian:/sys/bus/w1/devices $ ls -al
total 0
drwxr-xr-x 2 root root 0 Dec 20 01:17 .
drwxr-xr-x 4 root root 0 Dec 20 01:17 …
lrwxrwxrwx 1 root root 0 Dec 20 12:06 28-3c01e076c7f8 → …/…/…/devices/w1_bus_master1/28-3c01e076c7f8
lrwxrwxrwx 1 root root 0 Dec 20 12:06 28-3c01e076cfad → …/…/…/devices/w1_bus_master1/28-3c01e076cfad
lrwxrwxrwx 1 root root 0 Dec 20 10:12 28-3c01e076df33 → …/…/…/devices/w1_bus_master1/28-3c01e076df33
lrwxrwxrwx 1 root root 0 Dec 20 12:06 28-3c01e076e719 → …/…/…/devices/w1_bus_master1/28-3c01e076e719
lrwxrwxrwx 1 root root 0 Dec 20 12:06 28-3c01e076e927 → …/…/…/devices/w1_bus_master1/28-3c01e076e927
lrwxrwxrwx 1 root root 0 Dec 20 12:06 28-3c01e076f728 → …/…/…/devices/w1_bus_master1/28-3c01e076f728
lrwxrwxrwx 1 root root 0 Dec 20 12:06 28-3c01e076fc36 → …/…/…/devices/w1_bus_master1/28-3c01e076fc36
lrwxrwxrwx 1 root root 0 Dec 20 01:17 w1_bus_master1 → …/…/…/devices/w1_bus_master1

openhabian@openhabian:/sys/bus/w1/devices/28-3c01e076e927 $ cat w1_slave
60 01 55 05 7f a5 81 66 69 : crc=69 YES
60 01 55 05 7f a5 81 66 69 t=22000

BTW, I disabled meanwhilwe the OWServer component/binding as I assume it is not needed for local sensor access with the kerner driver providing the above /sys entries

Module Size Used by
w1_therm 28672 0
w1_gpio 16384 0
wire 36864 2 w1_gpio,w1_therm

Then I added two times onewiregpio:sensor on different sensors, like :

UID: onewiregpio:sensor:4729349b0a
label: Temperature Sensor A Umgebung Raumluft
thingTypeUID: onewiregpio:sensor
configuration:
  gpio_bus_file: /sys/bus/w1/devices/28-3c01e076df33/w1-slave
  refresh_time: 5
  precision: 2

Openhab shows this sensors in green/online. For my understanding this is the proper binding of for the sensor and I need nothing more.

But as soon as I try to add a link to one of those things (select “channels” tab from the thing, select the suggested default temperture (channel?), press “add link to item” , select “generate a new item” and click on “link”) , the item (number-temperature-point) is created and linked, but the channel temerature turns on red/ERROR:COMM. Any widget in the Web-UI with those items stays empty. Also creating manually items and add a channle link afterwards does not work for me, I can select an thing, but no channel is offered and no save button is offered. Removing the link/channel turns the thing back to green/online.

The log tell me “2021-12-20 13:50:34.834 [INFO ] [ab.event.ThingStatusInfoChangedEvent] - Thing ‘onewiregpio:sensor:1e112f05eb’ changed from ONLINE to OFFLINE (COMMUNICATION_ERROR): Error reading GPIO bus file.” , but the fs data is accessible.

Does anybody see what is wrong in my chain or sensor setup ?
BR

Update : After switching over to textual description of things and items, I got the channel binding established now. I still do not understand where exactly it messes up in my try with the GUI. Attached JFYI the 7 temperature sensor chart from the RPI operating now remotely acceses over cloud service. BR.