Operate only once

General
1

I have a temperature sensor and a window opening
i have it configured through the switch node as pictured below
However it is switching an already Open, On every 3-4 minutes and i am woried this will burn out my relay

Which node would i use to send the Open command only once, or only trigger open if closed
im thinking the Trigger State.

node
node643Ă—553 26.2 KB

2

Add an RBE node which will only pass messages with a payload different to the previous one.

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3

i think my problem is the temperature is always changing i have a switch splitting the temperature 3 ways above 16 degree opens the window but it will keep triggering at every temperature transmitted above that

4

If a relay is already ON (energized), then it shouldn't matter how many times somthing tells it to turn on again... ON is already ON.

Now, turning ON then OFF then ON again and again, that is the wear and tear part... is that happening?

5

Yes i have the relay on only for the time it takes to open the window, as i wanted to isolate it encase of battery drain, (i might be worrying about nothing)

I think i have solved it by using a change node, to fix the changing temperature coming out of the switch node, to pass on the message as "above" or "below" then use the suggestion from @Colin (thanks) to use an RBE node

6

I meant to use the RBE at the end of the flow, just before passing it to the outside world, which I think is what you are saying.

7

or may be this:

You could use a variable in your flow:

  • for example you could set a flow.windowstate variable with a change node to a "open" value when a command to open the window is executed, and to a "closed" value when a command to close the window is executed.
  • use a switch node that will check the value of the flow.windowstate variable before executing the open or close command:
    For an open command:
  • if flow.windowstate is 'open" -> do nothing
  • if flow.windowstate is "closed" - > execute open command

This way you wouldn't have twist your brain to deal with the constant temperature changes, as the commands will be ignored if the window is already in the required position.

8

Use the smooth node - have it take in (say) 10 temperature readings and smooth them out - then use the RBE node after that

Craig

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9

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