Emoncms input key range


Since you added the possibility to report informations like PF, it start to be nice to have the possibility to have more than 29 input keys.

From where is this limitation coming? Emoncms, iotawatt memory/resources ?


It is somewhat arbitrary, but there are a host of issues with large output scripts, from the size of the config file json which must be parsed and processed dynamically every time you make any change to the configuration, to the heap required to save the scripts, labels and constants, to the size of each dataframe in the HTTP packets - especially during recovery/bulk update.

Emoncms stores all of this in individual feeds, which you now pay for and can consume a lot of storage. I have to wonder if anyone needs to have that volume of data on a regular basis.

IoTaWatt’s datalog, on the other hand, can produce all of that data from just two saved values per input, and has 5 second resolution for the most recent 12 months. It is more efficient in flexibility, storage size, and organization.

You might consider uploading the data you need for overview dashboards, and then using the IoTaWatt graph facility for detailed analysis. The new ALPHA releases offer password protection so you can expose it on the internet and access much like an eMonPi.


I ordered a second IotaWatt and I plan to have only once the mains.
Would it be possible to copy (or export) all the data from IoTaWatt and import it to a local installation of emoncms?

On this way I could store all the data of all IoTaWatt on a central place ?

PS: Sorry I’m creating support load those days… I did not tell that you did a good job and I understand that is a challenge to select what to add as feature in order to be able to keep a certain direction and a certain code quality :wink:


You can export data from IoTaWatt to EmonCMS. With 02_03_08 you can initially upload any historical data as well. The two IoTaWatt should use different EmonCMS node ids.

IoTaWatt and EmonCMS take a completely different approach to data storage. There is no way to upload “all” of the data. You can specify what you want to upload, And that is what will be available on EmonCMS.