Stop moving X-axis of a chart if no data is received

[nosered1966]

Hi all,

as you can see in the screenshot below, I have a chart (the lower one in the screenshot) which stops drawing data correctly / by intention (at about 12 o'clock in this example) but the X-axis is moving on.

Is there a way to stop also moving the X-axis when not data is received?

Thank you very much!

Kind regards
Thomas

[E1cid]

As far as I know the x-axis should not move if the chart is not receiving any messages, are you feeding in any null values? Add a debug to all nodes feeding into chart node to see if any messages are still coming in. a message will null value will move the chart on.

[jbudd]

A simple chart (only one line) does not do that for me.
Are you sure you are not sending NULL values to the chart?

[nosered1966]

You were right, thank you both!

And it was more than NULL values ...

[nosered1966]

Hi @E1cid & @jbudd,

unfortunately I was hasty with my answer two days ago.

As you can see in the screenshot below, the X-axis of the chart at the bottom is still moving, although no data is output to chart (=> no data is shown in the debug nodes msg_1 to msg_6 because in each function node the same code is implemented).

Any idea why the X-axis is still moving?
Maybe moving of the X-axis cannot be prevented on principle?

The X-axis is moving after switching from on dashboard tab node to another or after refreshing the dashboard web page.

Thank you and kind regards
Thomas

[jbudd]

Yes, I think you have found a bug!

A simple flow that draws two charts on the same dashboard tag:

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Both charts work for 10 data points, then the second one ceases to be updated. Correct so far.

Refresh the browser and the x axis is redrawn for both charts. Surely this is wrong?

Edit - well the chart is set to X axis 1 hour or 1000 points but I still wouldn't expect it to redraw the axis with no incoming data

[E1cid]

here are two work arounds to fix chart when you stop updating

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First will send chart history after no messages received for x seconds

The second createsthe chart from stored data and new incoming value.

[nosered1966]

@jbudd Thank you!

And who is responsible for fixing bugs in Node-RED?

[nosered1966]

@E1cid Thank you, I will have a look on it as soon as I have enough time for it...
Kind regards
Thomas

[jbudd]

I don't think anyone is "reponsible" for fixing bugs, but we do seem to rely a lot on just a few core developers.

One of the best things about Node-red is that those core developers often share their advice and knowledge in the forum.

The procedure is to raise an issue on github, then anyone is free to offer a fix.