Graph shows no data unless input changed

Dashboard
1

I have made a simple dashboard, the problem is if the slider is not changed, the graph is frozen until the slider is being moved.
If I do not change the slider value even for an hour, I got nothing instead of a steady line.Would you please help if you know any idea how to let the graph stamp the time and the slide value every second whether it is changed or not?

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Appreciate your support.

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One way is to disconnect the slider from the chart and instead save the slider value in a variable.
An inject node can be set to inject the variable value every second.
Edit - sorry I changed the variable name from lastvalue to slidervalue but didn't change the node labels to match.
Untitled 5

3

Or connect the slider to a Trigger node configured to repeat the last payload.
image

1 Like
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Much better!
Why didn't I know the trigger node could do that? :rage:

1 Like
5

Thank you very much for your answer. I have tried this way but still, I got nothing. Colin's solution worked. Thank you.

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Thank you very much. It worked very well, except when you started the dashboard, the graph was not shown until data changed then keep working as I wished perfectly. so if the temperature is not changed for some time, the first run of the dashboard will show an empty graph as the first image I attached.

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Initialise the slider and the trigger node with an Inject node set to fire on startup with the initial value you want.

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It is a recent addition I think.

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I guess the slider has no initial value until you move it. I will try to use real sensor data. However, I have learnt from your way how to use the exchange function. I am very beginner in Node-Red. Thank you

10

I recommend watching this playlist: Node-RED Essentials. The videos are done by the developers of node-red. They're nice & short and to the point. You will understand a whole lot in about 1 hour. A small investment for a lot of gain.

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For about 5 years but not often used.

12

When you get to my age, five years is recent :slight_smile:

2 Likes
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