Gas monitoring and feed types

Hi All, I have set up a basic system to monitor a single CT and also taking a feed from a U6 gas meter using a reed switch.

I have modified the sketch to handle both and made it send the single pulse and also a value of 111.

The 111 is based on calculations from my bill that 1 cubic meter of gas is just over 11Kw. and I believe there are 100 pulses per cubic meter.

how do I best configure the feeds to give hourly KW daily Kw etc. I have had a look round but cant find any detailed info on feeds.

Thanks in advance

Great concept by the way! keep up the good work


Paul Reed's picture

Re: Gas monitoring and feed types

Would it be better to configure your pulse value to '1', and do all the calculations in emoncms using the process list?

x 111
Power to kWh/d
log to feed



kismet's picture

Re: Gas monitoring and feed types

Thanks Paul, I do send the single pule as well so I will add feeds as you say and work from there


Thanks for the info 



Jérôme's picture

Re: Gas monitoring and feed types

The shortcoming of this method is that if the radio link is noisy, you may lose samples, and then your integration is false.

When you lose samples of CT measurement, you lose precision, but the data is interpolated, whereas if you lose a pulse here, you sum is just false.

I tried to do it another way.

The idea is to send not a pulse but a counter. This way, if you miss a pulse, then when the next pulse is received, it accounts for two, and interpolation does its job and only precision on the consumption profile is lost, not the total energy.

The difficulty is that the EmonTX can be reset at anytime, so you should expect to receive a reset counter. You need to figure out whether this is a reset or an overflow. The optimal threshold between what would be a reset and what would be an overflow depends on the counter's max rate. Robert details this in the thread I'm referring to.

I had begun working on this. More info on my profile, and in the code:

but this is (or was, as I left that aside for a moment) work in progress.


kismet's picture

Re: Gas monitoring and feed types

Hi Jerome,  that makes sense, I will also think about sending a count rather than a single pulse, I will sync with the meter reading and what I am loosing in the short term to judge the level of the problem.

I am still having issues with getting the data to log correctly  I have attached 3 screen shots 

the log seems to make sense as its showing peaks of 111 watts but the kwhd has a very small scale, not sure where I am going wrong

thanks again Paul

[Edit: tick 'List' after you've loaded the files to make them visible - RW]

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