Sample rate limits and data resolution


#1

Hi,
what is the minimum sample rate which I can get values from IoTaWatt?

I need dataentrys of the values (voltage, current, power of each of the 14 feeds) at least with an timestamp every second (better 0.5 s). Is this possible with an local server?

thanks frank


#2

The minimum interval is 5 seconds. You can scrape some numbers with the status API more frequently, but they are not time stamped and are subjected to a damping algorithm.

The 5 second data is an accurate time weighted average of typically about 10 measurements taken during the interval.


#3

Ok, that is too slow for my application.
Would it be bossible to customize the software to realize 0,5 seconds measurment? Or is this hardware limitation?
Thanks frank


#4

I’ll bite… I am really curious as to what your application is that requires sub-second power measurements?


#5

Depending on your line frequency, IoTaWatt samples one input every 24 or 30 ms. That’s the basic hardware capability. The firmware is designed to be an energy monitor, to track energy (kWh). Power (Watts) Is a byproduct. ioTaWatt isn’t a power meter.

IMO if you have a need for subsecond data, you would need to write a completely different firmware that doesn’t have a web server and data communications that can compromise subsecond sampling. Just a straight datalogger that samples and records to the SDcard. There are probably better tools for that already available.