Change from dashboard

Hello !! I would like an explanation of how to change a value from the dashboard to a node. I am working on a heating system where I have a ds18b20 sensor. I want to control a relay with a value that I can adjust from the dashboard.

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if you want to set a temperature in the dashboard, the way I would approach this is to save the temperature you set as a global value using a change node.

Then in your sensor flow you can check if msg.payload is greater of less than your set global value, using an if statement in a function node

Please wrap code in triple or single back-ticks so that it can be copied and read more easily. Thanks.