No InfluxDB entry for Number result from EXEC binding

I just got a REHAU airquality sensor I put into my Raspberry Pi. Together with a small tool (“airsensor”) that reads the values from the sensor and put them to STDOUT, I hope to have a cheap monitoring for my Homeoffice (which I have to use quite regularly currently, thanks to COVID-19).
On command line it works quite well, “/home/openhabian/rehau/airsensor -o -v” returns just the value I need:

openhabian@openhab:~ $ /home/openhabian/rehau/airsensor -o -v

The resulting item I defined is:

Number:Dimensionless AirSensor_Output  "Rückgabewert Luftgüte"  (gAirSensor) {channel="exec:command:airsensor:output"}

I then configured a Thing with this command, REGEX transformation (which should not be used here) and 60 second interval. In influxdb.persist I added a line to “Item”:

AirSensor_Output     : strategy = everyChange, everyHour, everyMinute

The problem I face: I don’t get any value into my InfluxDB. When I change the datatype for the item to String, these are imported into the DB, but of course it’s not possible to create a grafana graph for it :frowning:

Could someone point out what’s wrong?

Exec binding output channel is of String type. That’s it, there is no Number type channel.

Unfortunately there are as yet no profile types available to match a String channel to a Number Item.

Your recourse is to output to a String Item, and have a rule triggered on update parse the string to a number and post to a Number Item.

Ah okay, thanks for the confirmation. I didn’t get an error, but this explains a lot :slight_smile:
I will do as proposed then …