Graph local EmonCms with null values (input with serial Arduino)

Hi all,

We have a problem showing the realtime data on our local emoncms. The data in the graph is not showing for the power feed and when looking into the source code, we find NULL values for the data points. Is there something we are looking over ?

This is happening with the feed we crated from a multiplication of two inputs, namely the power_online_W feed.

We are working on the emonpi.local platform with local AP, without internet connection. Raspberry Pi Model B+, emonSD-30Oct18. We are installing a DC monitoring system with inputs from Arduino via serial connection. This is not our first setup, with the Raspberry Pi 2 Model B and emonSD-07Nov16 we had it working last year.

What log can I post for more clarity of the issue ?

Thanks already!

If there are many NULL datapoints that would suggest that either the input updates are inconsistent/unreliable or the chosen feed type isn’t right for the update interval.

eg if an input is updated every 60s and you choose a 10s fixed interval feed type, each valid 60s datapoint will be separated by 5x NULL 10s datapoints. Or if you have a data source that is only active 50% of the day, it will register NULL datapoints whilst it is inactive when you use a fixed-interval feed type.

If an input is regularly updating at 10s intervals it should be matched to a 10s fixed interval feed, likewise a 60s input update to a 60s fixed interval feed etc