Ok, makes perfect sense, now it’s clear to me, thank you guys. I only assumed the turns ratio mattered because of the information on the calculations on the “interfacing with arduino” page, that mentions only the turns ratio. What about the readings i get, even if I’ve disconnected the sensor, any idea why i get them ?
It is noise. There are very many threads about this, mostly on the old “Archived” forum.
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I’ve sent a PM to YHDC’s representative who has an account here, asking for that file in post 16 to be checked.
(See About split core CTs SCT-013 family)
Hi,
I would like to mesure the power consumption of my house with a SCT013.
As mentioned in this post , there are many version with output voltage or current :
SCT-013-000 Primary AC current: 100A Secondary current: 50mA
SCT-013-005 Primary AC current: 5A Secondary voltage: 1V
SCT-013-010 Primary AC current: 10A Secondary voltage: 1V
SCT-013-020 Primary AC current: 20A Secondary voltage: 1V
SCT-013-030 Primary AC current: 30A Secondary voltage: 1V
SCT-013-050 Primary AC current: 50A Secondary voltage: 1V
SCT-013-060 Primary AC current: 60A Secondary voltage: 1V
SCT-013-000V Primary AC current: 100A Secondary voltage: 1V
I would like to mesure with a SCT013 connected to an nodemcu ESP8266.
What is the best choice of SCT013 to purchase?
Do i need to add a burden resistor ?
thanks
We do not advise using the ESP8266 for energy monitoring. It’s inaccurate, it cannot take readings sufficiently quickly and you cannot obtain accurate results.
I strongly advise you to use an Arduino Uno, which is much better suited to energy monitoring, and for which we are able to offer much better support.
To answer the original question: whichever suits your purpose. If you use a voltage output type, the burden is internal (that’s why it outputs a voltage), so you must not have a second external burden. If you use the ‘proper’ c.t. with a current output, then the burden is what converts the current into a voltage that the ADC expects.
Ok i Will use an arduino uno as you advise.
But what about sct013 which one do you advise?
Thx
Hi
I am a little bit lost in that SCT clamp
If i am right there are 2 kinds of SCT
1/ SCT-013-000 Primary AC current: 100A => With current output
2/ SCT-013-005/010/020 Primary AC current: 5A => With voltage output
Let 's explain my project.
I want to use an ESP32 to read AC consumption at home (230V)
questions:
1/ What is the best solution in term of CT Clamp (current or voltage) ?
2/ How to interface CT Clamp with ESP32 micro controller ? do i need a dedicated card ?
3/ What library to use in arduino ide?
Thx in advance
Best Regards
Welcome, Benoit, to the OEM forum.
Not really two kinds of c.t. (I don’t call them “clamps” - it is a bad translation.) A current transformer is what its name says, it works on current. You can turn current into a voltage by passing it through a resistor - the resistor or instrument that provides a load for a current transformer is called its “burden”. The difference between the two 100 A c.t’s, the SCT-013-000 and the SCT-013-000V is that the latter has its burden resistor inside the case and so the output is a voltage as you say, if you need a voltage rather than a current from the SCT-013-000, then you must provide the burden resistor.
It depends on what you want to do. If you have an ADC that can handle 1 V rms (in this case), then you can use the voltage-output type. If you want a different voltage, it is probably better to use the current-output type and choose your burden to give you the voltage you want.
(Looking at the ESP 32 data sheet, it recommends for best accuracy a range that goes from 100 mV to 950 mV - for a pure sine wave, this is 300 mV rms centred on 525 mV d.c. For this, a SCT-013-000 with your choice of burden would be best. But the recommended input range of 0 - 2450 mV is 866 mV rms, so if you can tolerate a restricted input current range (i.e. 86 A with the 100 A c.t, 4.3 A with the 5 A c.t) then you can use the voltage output type.)
It might be helpful to know that the YHDC current-output c.t. and the voltage-output types are almost identical (the voltage-output has slightly fewer secondary turns on it), and it’s only the internal burden that changes between the different current ratings - 372 Ω for the 5 A to 20 Ω for the 100 A.
I don’t believe you will need anything else, I’m not familiar with the ESP32 so I cannot tell you what you will need to do.
The OEM libraries “emonLib” and “emonLibCM” were written specifically for the Atmel ATMega 328P processor, so they cannot be used directly with the ESP 32. However, there is nothing to stop you from copying the core code in either library and adapting it for the ESP 32. The areas you will particularly need to look at are switching the input multiplexer, starting the ADC and getting the values out of the ADC.
I’m sorry I can’t help and more with your second question, there are people here who will be able to help you.