I use serial port for communication. When I close the serial port, the chart of the dashboard will continue to draw the waveform for 10s instead of stopping the drawing immediately. What is the reason for the delay?

[Lep]

My node design is shown in Figure 1. The serial port input is connected to a function Fecg_raw(), as shown in the second picture.

[stephane.legargeant · Accepted solution]

Hello

When the throughput of data is too high, there is some delay in the display. Some data can be buffered by the serial port driver, by node-RED backend and by frontend. When many data are sent from backend, there can be some delay in the display.

You can try to analyze what happens:

• reduce the number of variables displayed or set a data rate limiter to see if it changes the delay.
• slow down the data sent on the serial port to see if there is less delay
• add some log function at different point to see when the data really stops in the flow.
• check that port is closed immediately.

Best regards

Stephane

[Lep]

Thank you for helping me since I used stm32cubemonitor.

I benefited a lot from your help.😁

[Piranha]

> When the throughput of data is too high ... node-RED backend

https://en.wikipedia.org/wiki/Node-RED

So it's basically a web page, which means that by design it's incapable of delivering a decent performance, especially for real-time tasks.

[Lep]

Thank you😁