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Use 'total pulse count to pulse increment' - this needs a feed to track the last value of your input (i.e. a feed you'll never otherwise use, or visualise) and returns the delta between the latest and immediately preceeding readings.

You can then log this to feed, and it will give you fine-grained usage.

I'm working on a time-of-day filter process which would allow you to selectively log to different feeds, i.e. a feed for morning, afternoon, and evening (or whatever). It doesn't currently work because it can't support daylight savings...

Would  you mind running through how you would set this up in emoncms as I am also trying to do the same - this time for a rainfall counter.  I have had a try with the 'total pulse count to pulse increment' process but it only seems to give me the pulse number from the input. 

Much appreciated

Gary

Gary, you have a different approach since your input is not the total rainfall ever recorded, whereas the OP has a meter that reports the total electricity ever used: this is what "total pulse count to increment" turns into pulses-per-call-in.

For your rainfall input I would have

• log to feed (instantaneous rain)
• accumulator (all the rain ever)
• kWh to kWh/d (daily increase in accumulator)

You can then visualise the third 'daily totals' feed as a bar chart, and instantaneous feed for debugging / realtime rain.

Sorry i should have said - I am intercepting a signal from an outdoor weather station that keeps a cumulative total of bucket tips that it sends out in each data packet - the base station would then do the difference calculation.  Every now and again the count will roll over and restart from zero so I will get the occasional iffy reading to edit but that should not be that often (unless we have another crazy run of storms).

Many thanks

Gary

Ah, OK. In that case "total pulse count to increment" is your man. As you say, after that process is added you get just the number of pulses since the last time you intercepted a transmission. If you do this first before anything else, you can add the three steps in my post above and it will work as intended.

Having a senior moment, do I not need to log to a feed first so

log to feed

total pulse count to increment

accumulator [I can probably drop this as mm per day is more useful for me]

kWh to kWh/d for daily rain?

One extra tweak - I am currently on emoncms v6 on the RPi and waiting for v8 to stabilize before making the jump to the HDD install version.  I have pulse difference in the menu which seems to be a blend of steps 2 and 4 above.

Many thanks

Gary

The simplest thing is to have just have one process - kWh to kWh/d straight from your input, and that will work to give daily rainfall. However, it won't keep count of total rainfall over time, rainfall at each call in (the raw log) and so on.

The main issue is that if you don't use the pulse total to pulse count / accumulator / kWh to daily chain then it won't cope so well if your rain gauge resets or submits a lower number (for whatever reason).

I am having a quick go on the emoncms website with the rain feed but not sure it is working.

I have the raw figure being logged (every 2 mins to match what I expect to pick up) - nice and sunny at the moment so should be a steady "190" each cycle

Next I went to add the "total pulse count to increment" and I have an interval to set - is this correct?  I thought the function simply calculated the difference from last to current feed value.

Then when I go for the accumulator it also has an interval setting.  I have an accumulator set up for gas pulse counting and am sure there was no interval when I set that up.

I am using Chrome on Windows if you think it might some odd browser behaviour.

Schism,

Can you explain how to achieve this?  Right now I have:

1 Log to feed (kwh)
2 kWh to kWh/d (kwh-hwhd)
3 Log to feed (lastKwh)
4 Total pulse count to pulse increment (kwh-inc)

This doesn't seem quite right.