Pulse counting vs instantaneous power

Hi all,

even if in the documentation is clearly stated:

Unlike clip-on CT based monitoring, pulse counting is measuring exactly what the utility meter is measuring i.e. what you get billed for. Pulse counting cannot provide an instantaneous power reading like clip on CT sensors can. Where possible, we recommend using pulse counting in conjunction with clip on CT sensors.

Is there any chance or workaround to create a visualization of real-time power ?

Thanks !

No, because the meter only emits a pulse after a set quantity of energy has passed through it. The meter will be labelled to show what that quantity is. At high powers, the pulse rate will closely match (but will always follow in time) the power measured by a c.t. At low powers, you have no indication of power until a pulse is triggered, so it can only give you the total energy, from which you can deduce the average power, since the last pulse.

Hi sorry to hijack the post but this is exactly what i was searching to do.
When you say you can deduce average power since the last post", is this just through using the ‘Average’ function of the graph software?
I am not fussed on being totally accurate, would just like a display of average minute and half hour Power.
Any reply would be greatly appreciated.

Hello Tyson, welcome to the OEM forum.

I’m not an emonCMS expert - but I think it’s built in to the pulse handling mechanism. I’ll let those who know emonCMS correct me!

Same here, sorry for hijacking this thread but I am too interested in displaying the instantaneous power.
Having a power meter with 10.000 pulses / kW, the time interval between two pulses is extremely small, even on a very low consumption (1 pulse every two seconds for a 10 Wh consumption, if I calculated it correctly). So this should enable me to have a really accurate instantaneous power reading while only using the pulse reading.
Now I am just gathering information and reading the documentation, before purchasing or building anything, so I would really like to know what the system can or cannot do.

Thank you in advance,


Hello Romeo, and welcome to the OEM forum.

The standard emonTx sketch measures the power (using the c.t’s and a.c. adapter) over a period of 200 ms every 10 s and reports that, along with a count of the pulses recorded over the preceding 10 s. If you have an emonPi, it does the same but every 5 s. Therefore, what you see from the the c.t. is a snapshot of the almost-instantaneous power measured just before it reports to emonCMS, but the cumulative energy over the period since the last report, from which you can infer the average power over that period.

In the case where the quantity of energy per pulse is such that there are no pulses during the 5 s or 10 s period, it will report zero energy and from that you infer zero power. It might be that the c.t. will report power - it depends on what one pulse equates to.