Scaling timestamp

Report bugs
#1

Hi, I am working a process in HVAC system, monitoring discharge and suction pressure on a chiller.

The sample time is about 15 minutes (or 900 seconds), hence, the csv file fail to upload.
The pressure signal cycle is about one day.
In order to test, I am scaling the timestamp on 1/1000.

After results, how can I scale again in order to have the correct WA or Arduino library?

Regards.

#2

Captura de Pantalla 2021-08-17 a la(s) 2.24.30 p. m.
Captura de Pantalla 2021-08-17 a la(s) 2.24.30 p. m.1054×331 63.7 KB

This is a picture from de pressure signal.

#3

Hi @julianflorez,

You will need to scale the EI_CLASSIFIER_MS in your code. This is the Arduino accelerometer example (not scaled):

// Allocate a buffer here for the values we'll read from the IMU
    float buffer[EI_CLASSIFIER_DSP_INPUT_FRAME_SIZE] = { 0 };

    for (size_t ix = 0; ix < EI_CLASSIFIER_DSP_INPUT_FRAME_SIZE; ix += 3) {
        // Determine the next tick (and then sleep later)
        uint64_t next_tick = micros() + (EI_CLASSIFIER_INTERVAL_MS * 1000);

        IMU.readAcceleration(buffer[ix], buffer[ix + 1], buffer[ix + 2]);

        buffer[ix + 0] *= CONVERT_G_TO_MS2;
        buffer[ix + 1] *= CONVERT_G_TO_MS2;
        buffer[ix + 2] *= CONVERT_G_TO_MS2;

        delayMicroseconds(next_tick - micros());
    }

You could also implement your own delay mechanism as I suppose your device goes to (deep) sleep between each sample. As long as you fill the buffer with the expected number of features this should work well.

Aurelien

2 Likes