Graphing Temperature Problems

Emoncms
#1

Hey Everyone. Fairly new to Emoncms. Running the application on a Raspberry Pi. At the moment all my data is imported via scripts which call the Input URLs once every few seconds. I’m tracking several electrical and temperature nodes.

All my inputs and feeds work well. The visualization tab and Dashboard shows everything as it should. In the graphing module the feeds related to energy (volts & watts) display fine but the ones related to temperature (F) are not displaying correctly. When first opening the graph the Y-Axis shows a range of -1.00 to 1.00. (The actual data is 50F to 70F.) When I manually change the range I still see nothing. BUT, if I zoom in to a very short time span – about 70 minutes – the graph suddenly appears. As soon as I zoom out, the data disappears.

Any idea how to fix this problem?

#2

Welcome.

What is the feed engine? You can see this on the feeds page (here showing PHPFINA and PHPTIMESERIES)…

image

#3

Thanks. The engine is PHPFINA. I think I might have found the problem: The feed was created with a 10s interval but the data arrives every 60s. I just created a 2nd feed with the correct interval and so far it’s graphing correctly.

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#4

Yes - that’s the problem. You have 5 “NULL” values between every 6th valid value. The graph picks every nth value (depending on the horizontal scale) to plot and if that happens to be one of the nulls, you get nothing. There’s an 83% chance of that.

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