"Connection Lost" only on Tablet


i use my old Asus P027 Tablet for Smart Home Center in my Floor.

Before i completely changed to Node-red, i used Openhab Dashboard. It worked fine.

Now i use Node-red Dashboard for a while and only on my Tablet i have "Connection Lost" and reload the Dashboard.
Video: https://www.youtube.com/watch?v=NA4hd1asmGg

Any Idea?
On the Browser of my PC and Smartphone i didnt have this Problem. Browser is Firefox.


Model P027
Android version 6.0; WW_ZenPad-; SDK23
CPU 6 cores; AArch64 Processor rev 2 (aarch64) mt8173; Max: 1703,0 MHz; Min: 507,0 MHz
Display 2048 x 1536; DPI: 320; Evaluated Size: 8,0"
Touch screen Multitouch 10 points
GPU PowerVR Rogue GX6250; Imagination Technologies; OpenGL ES-CM 1.1; OpenGL ES 3.1 build 1.5@3830101
RAM 4096 MB (3921 MB available)
Flash 64 GB (58.242 GB actual); 2 GB (1.874 GB actual) (see memory map tab)

Which WiFi are you using?

2.4gig or 5gig?

I notice the WiFi signal strength isn't exactly 100%.

No, not the cause, but it won't be helping.

Oh, something else:
Can you check the load on the tablet? How hard the processor is working.
If the flow has a bit of bad stuff in it causing a high load, that can contribute to this happening too.

You have some charts in there. Can you try testing it without those charts (or without updating the charts) ?

At least 2 charts I can see are configured for 24 hours. And there is 4 and 5 datasets per chart. It really depends what is the rate of input for chart but you can calculate the count of data-points you r charts needs to be handle. At some point there is limit. And that limit is what you see - The connection lost.

It is discussed here in forum many times and there is many advises given how to handle this situation.
Do search in forum in therms of slow/unresponsive dashboard with charts.
Basically what you'll need to do is to reduce data-points for charts. Many ways to do it. And it depends what is the meaningful readout you are expecting.

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move the Charts to another Tab solve the Problem. How many points are Max?

Other Devices dont have Problems with the Charts, incl.Mmy Smartphone.

There is no direct answer to that question. It is combination of device capabilities, browser, other things the device/browser needs to do at same time, the page set up and many many more things.
But if you'll do the calculations based on the device you are seeing the connection lost, then that is definitely max for that device in current conditions.

Yes, that helps to get your main page responsive and not to fall into that trouble, but will the page/tab with charts be better? Probably not.

The charts in node-red are plain charts. Unlike for example grafana where a lot of optimizations is done under the hood by default, you have no need to even think about such problems. Well, you can kill the browser with them too, but that's another story. But for raw chart libraries the data optimization is left for user to figure out.

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There is no real max - but send more than is required and you will slow things down.

The issue is sending more points than the size of your chart.


  • your screen = 2048 x 1536; DPI: 320; Evaluated Size: 8,0"
  • your chart is approx 1/3rd of the screen wide
  • therefore 2048 / 3 = 683 pixels wide
    therefore, there is no point in sending 10000 points to a chart that only has 683 pixels on screen.

No i mean, the main Tab is fine now. Now i deleted the moved charts and the backup Tab.

You are just overloading the device with too much data to handle in the charts. As has been suggested, reduce the update rate to the charts so that the total number of samples across the chart is not much more than the number of pixels.

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