charts updated too frequently

[kkennyy]

Hi,

First, let me congratulate the developer for this awesome pice of software, it really works great.

Now, i am running CumulusMX on a raspberry pi 2, connected via usb to an Aercus WS3083 (using fine offset with light sensor driver), got it set up ok with wunderground and website ftp updates, all great. Today i notices something strange though. My charts look odd regarding the update rate. My station gets updates every 10 seconds, so normally i would say graphs should be updated the same, with new data every 10 seconds. Usually, this is true, but after some time, the chart gets data every 1 second, and the plot looks really messy. I attached here an example, you can see the point where it all gets choppy. Seems that if i restart cumulus, the previous data gets replotted correctly, but after some time after restart, updates increase at a rate of each second. Is this some kind of interpolation or what? Is my station sending 10 records at that 10 second interval or just one? I don't understand how these values get plotted, please help.

I'm sorry if this question has already been answered, i searched the forum but found nothing relevant.

Thanks!

[steve]

Your station actually sends new data every 48 seconds. Cumulus adds a new entry to the graph data once a minute, when it's running using 'live' data. The graphs are pre-loaded at start up with data from the log files (as mentioned in the Cumulus FAQ). I suppose I could add an option to plot the graphs at a less frequent interval, if you would rather have less detailed graphs.

[kkennyy]

So you mean that when i restart, it plots logged data at 10 seconds interval, and new data is plotted at 1 second interval? I think 10 seconds would be perfect, as you can see the graph is nice and relatively smooth in the first part, but with 1 second intervals (after restart) is getting very mixed readings.

[steve]

No. When it starts up, it downloads any data from the logger that it needs to catch up from when it closed. It adds each entry downloaded to the log files. The interval of that data depends on the setting in your station.

It then extracts the last 24 hours data from the log file and pre-loads the graph with it. The interval in that data will be a combination of what you have the station set to, and what you have Cumulus set to - although it is sensible to have both set the same. The interval is typically several minutes.

It then starts reading live data from the station. The station supplies a new set of data every 48 seconds. Cumulus adds a new entry to the graph once a minute. Not 1 second, or 10 seconds, once a minute.

Every 10 seconds would not be a useful interval to use for adding new data to the graph for your station, as it only supplies a new reading every 48 seconds.

[kkennyy]

Yeah, seems i was a bit stupid about this and misread minutes for seconds. Sorry about this. I see now that indeed the plot is 10 minutes before restart, and 1 minute after, like you said. Thanks for the clarification though, at least now i understand the mechanism.

Would like to see a feature maybe sometime to customize the plotted interval. Seems like maybe a 5 minute refresh would be more suited. Of course if you also think it would be useful to have and it can be implemented.

Thanks a lot!

[daj]

Would like to see a feature maybe sometime to customize the plotted interval. Seems like maybe a 5 minute refresh would be more suited. Of course if you also think it would be useful to have and it can be implemented.

I'd like to see something similar in the future. The once a minute plot can generate some very messy charts. A 'nice to have' in the future

[steve]

Not too hard to implement (for factors of 60 minutes) - I may put it in the next build. Of course, I also get people who want the graphs plotted more frequently, but it's unlikely I'll be adding that any time soon.

[leforthomas]

it seems you can also change the interval on the station using this (but do not run at same time as cumulus) http://www.aercusinstruments.com/conten ... 20V2.2.zip
I haven't tried it yet though...

[steve]

There's also a small utility I wrote (for Windows only) , which is on the downloads page, which can set the station's logger interval. It runs without requiring installation.

[leforthomas]

Great!!! I will have a look now, thanks!!!!