Hi, I receive data from the serial port at 50Hz frequency each message. I need to add timestamp to each message, so I do as follow: msg.timestamp = Date.now() So the timestamps of the messages needs to be at 20ms each other (because 50Hz frequency), but in the debug console I am receiving inconsi…

Can you show us an example of what you are seeing? Note though, that nodejs is not a realtime system. Occasionally it has to do stuff like memory garbage collection, so to get reliable 20ms sampling you would need a significantly powerful processor. You would probably be better doing the real tim…

Hi, thanks for your answer. I am using raspberry pi with node-red. I need to read the serial data from external device, so I am using NR. I just need to add a timestamp to each packet from serial. The packets comes at 50Hz. I will make a screenshot of the debug window

This is the output from the debug window. The timestamps isn't at 20ms distance each other. {"timestamp":"1678573635206","P1":1.92,"P2":-0.51,"P3":4.86,"P4":-7.17} {"timestamp":"1678573635270","P1":1.92,"P2":-0.51,"P3":4.74,"P4":-7.17} {"timestamp":"1678573635270","P1":1.92,"P2":-0.51,"P3":4.74,"P4…

Of course here is the flow: [ { "id": "b39e02db3febcac7", "type": "tab", "label": "Flow 5", "disabled": false, "info": "", "env": [] }, { "id": "afe2a9717e167739", "type": "function", "z": "b39e02db3febcac7", …

I will have a look shortly. What is the speed node? Is it a contrib node, if so then which? Just in case it is corrupting messages and overlaying data from one onto the next one, disconnect it from the function node and connect the debug node direct to the function node to see what you are gettin…

I just put the speed node to measure the rate. Then I deleted it. The debug output is directly to the function

I just quickly ran this and for me it looks good. Probably it is the issue described by @Colin that it is not a realtime environment and if your pi is busy with other things it might become irregular. Calculated the difference between consecutive timestamps and it looks like this: [image] You ca…

[image] yzerman: The debug output is directly to the function Do you mean the debug you posted is not from the flow you posted?

What happens if you use a change node configured to set msg.timestamp to timestamp rather than the function node ? and then debug msg.timestamp (IE not re-organise the rest of the object) Next question - what hardware are you running this on ?

Serial port data at high rate problem with timestamp

General

Colin 13 March 2023 11:44 5

Can you export the serial node and the nodes after it up to the debug node please?

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Serial port data at high rate problem with timestamp

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