Dimmer reads 100, but sets correctly (e.g. 22) (modbus binding)

Setup, Configuration and Use Items & Sitemaps
1

[OH version 4.3.5]
I’m trying to create items/things for my new ventilation system using the modbus binding.

All is working well/as expected, apart from a dimmer control that I created to manually change the fans. The dimmer slider is working, but it never shows anything but “100”, while the fans are actually set at the value desired.

This is what log gives;

12:44:42.736 [INFO ] [openhab.event.ItemCommandEvent       ] - Item 'GF_Workshop_vent_manual_speed' received command 22
12:44:42.737 [INFO ] [openhab.event.ItemStatePredictedEvent] - Item 'GF_Workshop_vent_manual_speed' predicted to become 22
12:44:42.737 [INFO ] [openhab.event.ItemStateChangedEvent  ] - Item 'GF_Workshop_vent_manual_speed' changed from 100 to 22
12:44:45.423 [INFO ] [openhab.event.ItemStateChangedEvent  ] - Item 'GF_Workshop_vent_manual_speed' changed from 22 to 100

The thing (manual_speed of holding2) is setup like this;

Bridge modbus:tcp:recom2 [ host="10.1.200.49", port=502, id=1 ] {

    Bridge poller coils [ start=0, length=1, refresh=5000, type="coil" ] {
        Thing data vent_power [ readStart="0", readValueType="bit", writeStart="0", writeValueType="bit", writeType="coil" ]
    }


    Bridge poller holding [ start=2, length=1, refresh=5000, type="holding" ] {
        Thing data speed_number [ readStart="2", readValueType="int16", writeStart="2", writeValueType="int16", writeType="holding" ]
    }

    Bridge poller holding2 [ start=17, length=1, refresh=5000, type="holding" ] {
        Thing data manual_speed [ readStart="17", readValueType="int16", writeStart="17", writeValueType="int16", writeType="holding" ]
    }
}

The items is setup like this;

// Recom2 ventilation items
Switch GF_Workshop_vent_power          "Ventilation Power"                                            (GF_Workshop)                              {channel="modbus:data:recom2:coils:vent_power:switch"}
Number GF_Workshop_vent_speed_number   "Ventilation hastighetsinst."                                  (GF_Workshop)                              {channel="modbus:data:recom2:holding:speed_number:number"}
Dimmer GF_Workshop_vent_manual_speed   "Ventilation manuell hastighet [%d]"                           (GF_Workshop)                              {channel="modbus:data:recom2:holding2:manual_speed:dimmer"}
Number GF_Workshop_vent_manual_spd     "Ventilation manuell hastighet"                                (GF_Workshop)                              {channel="modbus:data:recom2:holding2:manual_speed:number"}

As can be seen, I have also added a Number representation of the manual_speed thing, and it shows the correct value (e.g. “22”) (“Ventilation manuell hastighet” below.

Skärmbild_20250829_130909
Skärmbild_20250829_130909814×139 8.87 KB

What am I missing?

2

So, today I tried to add

, autoupdate="false"

.. to my dimmer item, and this made the dimmer position stay directly after changing dimmer value, but a refresh of the page pulled it back to 100 again.

Maybe I am misusing the dimmer control, and it was never meant to operate like this, but given that it is actually changing the value, even if it does not show it correctly makes it partly useful anyway.