Archived Forum

What version emoncms? emoncms.org or local? Inputs page or nodes nodes module? 

Or more specifically what processes do you have at your disposal? 

Is the incoming data an accumulating total pulse count? or is it the number of pulses since last update? is the input data received regularly or sporadically ?  

To "scale" the pulse count to kWh you will probally need to multiply by 9.09 (1/0.11kWh) at some point, unless using a processor that requires a W input rather than KW so the "kilo" scaling should be factored in to. 

Many of the processes used for pulse counting do not seem to be available on emoncms.org or in nodes module so your options may be limited unless using the inputs page of a local install. 

Do you have kWh to kWh/d ? if not you may need to just use an accumulating total and a bar graph as that is the current trend, as used in "MyElectric"

Paul

Thanks for the reply

emoncms.org is where I am trying to achieve the result but I do have an emonpi gathering data from various sources before those inputs are sent to emoncms.org where i doo all my input and feed processing

I have an accumulating pulse count regularly transmitted from the emonpi to emoncms.org

Any guidance appreciated

Keith

The easiest way is probably to just multiply the input by 110 to get a Wh value (0.11kWh = 110Wh). You can do this in the input processing or in emonhub.conf.

Currently emonhub sends "number of pulses" with a "scale" of 1 and a "Unit" of p for pulse. By setting a scale of 110 and a unit of Wh it changes the pulse count to a Wh total system wide.

If you wish to stick to the "stock" emonhub.conf settings for your device to avoid any confusion when G&T do updates on the emonPi image then you can just add the scaling in at emoncms.org as the first process. Personally I would recommend the first (in emonhub) way as that is how emonhub is designed to be used, but that seems to go against the current flow, the choice is yours.

Once in emoncms and scaled to Wh, you can use the Wh accumulator if the pulse count is subject to rollover or resets. That process is designed to record only the increase of the last post and add it to the current value. Like a ratchet effect, if your device resets and starts from zero again, this process will continue logging a total based on the pre-reset value rather than dropping.

If your "pulse count" is never reset, i.e. a numerical count is passed from a meter or inverter, rather than counting led flashes, etc then you can just log directly to a feed.

Then, for the daily totals, you can use a kWh to kWh/d process or, using the barcharts as per "myelectric", just keep an eye on "kilo" scaling. You may need to scale by x1000 or x0.001 depending on which method(s) you use.

Paul

Thanks Paul, will try again this evening

Keith

I have a std gas meter reading in cubic feet with a rj11 port connected to an emontx3.2 via a small circuit to stop bounce etc. I then use the following to get KW and KW/daily. accumulatex0.01X2.83X1.02264x39.3x0.2777777log-kwhKWd

So 1 pulse is 1 cubic ft x0.01 converts to 100cf x2.83 converts to m3 x1.02264 is a volume correction factor used by gas co's x39.3 is calorific value x0.2777777 converts to KW

Some new meters read in m3 so the calcs are easy. It should say on your meter what it reads.

I think that the emontx3.4 has a pulse count input built in which MAY use a software debounce. This wasn't written when I did mine.

Please note that there are possible safety issue when doing this and your gas supplier might get funny!

Thanks both, recommendations taken on board, we'll see what happens overnight

Keith

Just to note. If you are reading pulses using a reed switch. Some kind of debounce will be needed. I seem to remember the hardware one which I built was recommended to be most reliable.

If you are reading a flashing led then no problem.

Thanks Webby

I suspect the pulse input on the EMONPi incorporates something similar as i do not heave a bounce issue

Keith