I have setup an emon power monit and it shows correct power but after sometime it start to show -ve power.
there is no change in setup and yes my current sensor direction is correct.
Any help will be appreciated.
Thanks
I doubt that anyone can help you with only that information. See the FAQ - that tells you what you need to tell us.
thanks Robert.
i have this controller
https://shop.openenergymonitor.com/emontx-v3-electricity-monitoring-transmitter/
and using with a light bulb to measure the power.
its reading correct data but after sometime it starts to give -ve power and i as i read on this forum they say -ve data measns you need to change the sensor direction but in my case it was working fine and the direction was correct. so direction is not an issue.
The standard current transformer - if that is what you have - is rated to 100 A. Your light bulb, if it is the incandescent type, will be drawing maybe about 1 A at 120 V, or significantly less if it is a compact fluorescent or LED lamp. So the C.T. will be working outside its rated accuracy range anyway. It is quite possible that the c.t. or the input circuit is picking up electrical noise from somewhere, even from the digital part of the processor itself, and if you are looking at no current or a very low current, this can appear as randomly fluctuating small power readings. So without knowing more about your installation, that is about as much as I can say.
its a 100A/50mA CT and the load current is 3.28A/120V.
its a pure resistive load. so its following all the rules. it reads fine most of the time but then suddenly will start giving -Ve power values and then i have to reset it and it will work fine and then same problem all over again.
Is there any possibility you are reversing the AC adapter (assuming you are using one) if you are in the US or EU with 2 pin plugs, reversing the AC adapter will have the same effect as reversing the CT(s) as the direction of either the AC:AC or the CT is only relative to the other.
What do you do to reset it?
Do you have just the one CT connected? if not, do any others show the same characteristics?
Are the -ve values equal in size to the +ve ones, just signed different or are the -ve values close to zero? under no load the CT readings can be +ve or -ve when “about” zero due to noise.
Do you really mean 100 A : 5 mA for your C.T, or is that a typo?
no there is no change in setup. i keep everything same and it does this.
to reset i just power reset the device.
no the -ve value is not equal to the correct +ve value. its just a negative number.
the load is connected all the time and the readings change to around -1.
I have to say I’ve never seen a report from anyone of a problem like this before.
Where are you getting the numbers from, the Arduino serial monitor or somewhere else?
Are you using the factory-loaded sketch or something else? If so what?
Have you changed anything in the sketch?
What are your DIP switch settings?
What are the units? 1 W, 1 A?