Basic Pulse question

Hi There.

Firstly apologies for the basic questions, Ive tried to get my head around this but I just can’t. I’ve followed the Pulse sensor guide but its not giving me all the information I’m after, I really hope someone can help.

So I have a ASHP with its own meter, I want to monitor the energy used by the ASHP using the pulse sensor and the meter. The pulse sensor is correctly attached and receiving good readings.

The meter pulses 1600 impulses per kWh.

I would really love to get the following feeds working:

  • Accumulative wh
  • Accumulative Kwh
  • Daily Kwh

If possible it would also be amazing to get:
-Kwh used between 00:00 and 07:00
-Kwh used between 07:00 and 00:00
-Current power (although I understand this would be estimated?)

Sorry if this is a really stupid question!



Welcome, Tom, to the OEM forum.

You’re not stupid for not knowing where to look.

I think you mean you can see a count of pulses on the Inputs page of emonCMS. What is that count doing - does it accumulate or do you see the count of pulses per some time interval?

Without knowing, I can’t tell you what you need to do, but I can tell you where to look. On the inputs page where the pulses appear, at the end of the line there’s a spanner icon. Click that and the Inputs processes appear. How to operate and set this up is in the emonCMS Guide - but not what to set up. How it works is the Input comes in at the top of the list, then you choose a ‘process’ to change the number in some way, and the result is either shunted off somewhere, or it passes down to the next item in the list. At the bottom, if falls into a bottomless pit and it’s gone forever. So the very basic operation is “Log to feed” - a feed is the storage mechanism on the SD card or disc.

Look at processes like “Wh accumulator” or “kWh accumulator”, " × " to scale the count into Wh or kWh, and when you have the units you want, “Log to feed”. The blue panel below gives you a note explaining briefly what the process does, and what is passed on to the next process.

The best way to learn is to try it out. You can always delete the feed and start again, but you lose that data.

(N.B. ‘K’ is degrees Kelvin, and it’s W for watts.)

Thanks for the reply!

Below is what I currently have setup

My questions are:

  • My pulse count_adjust is there to show log the value once the 0.625 adjustment has been done, but why is it different from pulsecount_wh
  • is it possible to log to feed usage within certain hours?
    -is it possible to get a rough idea of current power
  • in general have I got this set-up right?

Thank again for the help!



Did they start at exactly the same time?

You’ll have to ask somebody who knows more about emonCMS to answer that one - but I think it’s probably no. If it is, it’s not something built-in and simple to set up.

Not really. It can be done, but in my opinion the result is not very useful. The problem is pulses are historical, you only know the average power from the one before the last to arrive and the last to arrive, and so if you’re storing the pulse count regularly (as we do) and there are no pulses within the time slot, it reports zero power for that slot, then a double power for the next.

It look OK to me, but I’m not an expert. You’ll know in a few days when you have a number of complete days of data to look at.

I calculate a kW power from a pulse output on my heating system. I do it using a bit of code in Node Red and then feed the result back to EmonCMS (but you could MQTT it to the emonpi). Yes, it’s historical, but pulses are coming at a fast enough rate fopr it to be reasonably accurate - I do some smoothing on the calculated flow to stop it bouncing up and down so much, but it still does it as you can see in the attached.