emonCMS: combine feeds

I've got multiple CT's collecting the usage of each individual group (a total of 11). Is there a way to create one feed showing the usage of all CT's together? I've tried the "+ feed" process combined with a "Log to feed" but that doesn't work. 

I'd like to use the My Electric view but that only uses the data from a single feed.

 

Paul Reed's picture

Re: emonCMS: combine feeds

I've tried the "+ feed" process combined with a "Log to feed" but that doesn't work.

Why? I thought that's what the +feed was intended to achieve? It seems to work for me - although I haven't tried 11 feeds.
What do you get when you add feeds together?

Paul

JD's picture

Re: emonCMS: combine feeds

There are two similar commands:

+ feed

and

+ input

If you just want to add a bunch of inputs without doing any logging or processing first, then + input is what you want.

pb66's picture

Re: emonCMS: combine feeds

However, beware of using the inputs directly in input processing, if an input is accidentally deleted the consequence is quite drastic, where as a feed is far more robust. I discovered this the hard way.

http://openenergymonitor.org/emon/node/6194

 

IngmarVerheij's picture

Re: emonCMS: combine feeds

What doesn't seem to work - but I could interpret it wrong - is that if I add all input myself the value is different than what emonCMS gives me.

I've attached a screenshot for clarification.

Paul Reed's picture

Re: emonCMS: combine feeds

As per post #2 above..

What do you get when you add feeds together?

Paul

pb66's picture

Re: emonCMS: combine feeds

The calculation could be correct if each of those input values were current and the "Node:5 Groep 5" input was  -5 at the time it last updated. The process lists calculations are triggered when the host input updates and the resulting feed value should be a total of the host input plus all the added inputs at that point in time only.

To confirm it's adding up correctly place a "log to feed" right at the top of the chain to observe the input and then move it down one  "+input" at a time once you are satisfied it's updating with each input correctly.

Paul

 

Paul Reed's picture

Re: emonCMS: combine feeds

Paul, presumably this would not occur if he used +feeds instead of +input ??

Paul

pb66's picture

Re: emonCMS: combine feeds

I'm thinking it would probably work the same way using +feed. I think the calcs and the result would be the same, the benefit of using feeds is just it's more robust.

Another way of doing it maybe to just log each of the inputs to the same feed in it's own process list, that way when ever any input updates it add's itself to the running total (log to "ALL" feed),it wouldn't be dependent on another input updating to trigger it.

Paul

IngmarVerheij's picture

Re: emonCMS: combine feeds

Using +feed indeed gives a better result. The input I'm using is always 0 (it's the temperature of an emonTX3 which isn't connected) so I can easily add the content of 11 feeds to this one before logging it to a new feed.

Thanks for the support guys

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