Define item label for volume in db -100 to +12

Setup, Configuration and Use Items & Sitemaps
1
  • Platform information:
    • Hardware: unknown
    • OS: Windows7
    • Java Runtime Environment: Jetty(9.2.14.v20151106)
    • openHAB version: 2

I have created a item:

Number BiampAudio_Stage_Volume	"item Biamp Stage Volume [%.1f dB]"	    <soundvolume>		{ exec='>[*:python C:/openhab/conf/scripts/biamp.py "SET 1 FDRLVL 134 1 %.1f"]'}

and a sitemap:

Setpoint item=BiampAudio_Stage_Volume  step=2.5 minValue=-100.0 maxValue=12.0

Log:

2019-05-16 16:43:55.694 [DEBUG] [sql.internal.MysqlPersistenceService] - mySQL: Stored item 'BiampAudio_Stage_Volume' as '-46.5'[-46.5] in SQL database at 2019-05-16 16:43:55.678.

The Label dB disapears as soon as i click once on the setpoint up/down arrows.

Why?

I have a running item for Switch and String see here for a Switch sample

2

Which openHAB version 2, 2.4 perhaps?
Which UI is in use? (different UI have different widget implementation, so it may not be evident in all UI)

There has been work on setpoint widgets having difficulty with units. Your Item is a plain Number type without dimension, but that doesn’t mean the widget handling isn’t (mis)treating it like UoM.
So far as I can see, the latest widget version will not be in 2.4

3

I have openHAB 2.0.0.b4 Build #477
And i’m using BasicUI.

4

I expect you’ve realized that is three years old, there have been updates to setpoint widget since then.