Data reading and plotting

#1

Hello!
I am working on a project in which i need to send analogue value with delay 1 ms to MQTT and plot that value into the graph but unfortunately i failed after several tries.Kindly help me how to solve this issue.

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#2

There are three things there that you want to do.

  1. Delay for 1ms (this doesn't actually make sense. You can't rely on that sort of timing accuracy with node-red).
  2. Send it to MQTT.
  3. Graph it (presumably from MQTT but you have not made that clear).

Which part can't you do? If you can't do any of them then start with the first. However please explain what is the purpose of delaying it for 1ms before sending it to MQTT.

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#3

Actually i am new in Node red .
Problem: actually i want to do Fast Fourier Transform of induction motor current .The system frequency is 50 Hz .so 1/50=20ms this is 1 cycle period. 1ms mean we get 20 sample for one cycle to perform FFT.

HOW TO READ DATA IN NODE RED means how can we insure that the data is correctly received from node red side?

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#4

Node-RED is not a suitable tool for doing that sort of high precision timing. You would be better to do that in a separate application in a language more fit for purpose and feed the result into Node-RED.

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#5

Sorry, not sure what you mean. You say how can you insure the data is received from node red which suggests the data is available in node red and you want to send it somewhere. Explain further please. What exactly are you trying to do in node red?

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#6

any other way of doing this?

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