Show a room temperature once first of each month at 00:01

For reason of documentation I have to show a room temperature (rcvd from KNX) at least each first day of the month at 00:01 in the dashboard until the next value will be received next month.
Inject does not work because there are only days not month, cron plus debugs the fired time but I cannot read and write a KNX input value at this time. I dont know how to wire cronplus to KNX input to write the text to dashboard. Any ideas please


Can you get it to work with a normal inject? If yes, what do you inject into the KNX node?

Show us what you have so far.

I thougth this could work:

flows.json (2.1 KB)

but the result ist terrible:


No. That's not how it works. You need to store the temperature value somewhere and then grab it when the cron node fires and use that to display on the dashboard.

Send the temperature to a change node & store it in a flow variable.

Set up the cron nodes' entry Payload to send the flow variable that you set up in the previous step.


many thanks. It is working now perfect.

Therefore I want to ask if you can explain me how to show always two values (the value from the last month and the month before).


On the month output, instead of simply storing flow.Temperature do 2 things...

On 1st of month, in the change node (or function node)

  1. copy flow.thisMonthTemp to flow.prevMonthTemp
  2. copy flow.currentTemp to flow.thisMonthTemp

context is NOT persistent by default (e.g. you will lose the stored value if node-red restarts)
A better solution would be to use a database for storing temperatures every day & use a SQL query to get this/last/last2/last10 months temperatures when ever you want.

Alternatively, you can make context persistent by use file backed context

Thanks. In this case it ist better to show the figures in Grafana, because all values from KNX are copied to a timberwolf server und its database, or get them back from there.


If they are in a database already then presumeably you can read them back from the database in node-red if necessary.

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