Took longer than expected to get the CT sensor in, but it finally arrived today. I have been playing around with it, by starting with everything I have found which says to install a 10 ohm burden resistor.
after installing the 10 ohm resistor, the voltage signal is so low that the cheap multimeter I have can't even read it with an estimated 12 amps running through it from a 1500 watt space heater.
I managed to get 1 code to work and give me a signal of .01 whatever (too many codes and pages come and gone since then), but only when I put the heater on high. low setting which is roughly 800 watts, 6-ish watts, nothing. I can't help but think the resistor is too high, so I dug and dug and came across the following:
Cuts from: https://openenergymonitor.org/forum-archive/node/156.html
"Calculating a suitable burden resistor size"
1) Choose the current range you want to measure
The YHDC SCT-013-000 CT has a current range of 0 to 100 A. For this example, let's choose 100 A as our maximum current.
A) 30 A
2) Convert maximum RMS current to peak-current by multiplying by √2.
Primary peak-current = RMS current × √2 = 100 A × 1.414 = 141.4A
A)
SEN-11005: 30A x √2= 42.4264068 A3) Divide the peak-current by the number of turns in the CT to give the peak-current in the secondary coil.
Secondary peak-current = Primary peak-current / no. of turns = 141.4 A / 2000 = 0.0707
A)
42.4264068 A / 2000 = 0.021213204) To maximise measurement resolution, the voltage across the burden resistor at peak-current should be equal to one-half of the Arduino analog reference voltage. (AREF / 2)
Ideal burden resistance = (AREF/2) / Secondary peak-current = 2.5 V / 0.0707 A = 35.4 Ω
A)
2.5 / 0.02121320 = 117.851149 Ω Not having any clue about any of this, I have no idea if any of that is relevant or not. Do I install a 100 ohm resistor instead of the 10 ohm or will I be risking life-and-limb by doing so?
Maybe a heater doesn't produce the right wave(?). No clue.
I've tried it wired directly to gnd and A0, as well as the 2.5v method shown on openenergymonitor, though I don't have the capacitor, but sounds like that's just for over-voltage protection and I should never exceed 10-12 amps in reality while the calculations are based on 30 A.
What do y'all think?
I'm hoping not to need anything more than I have, but I will be going to a job on Monday that brings me within a few miles of SparkFun if I need to get something else to make this work.
Spec Sheet on CT By the way, Since starting this project the compressor this is going on has AGAIN had issues resulting in simples/johnson controls coming out again, now it is removed from the system and a normal garage compressor is in it's place. It was short cycling ever 47 seconds and they want to continue throwing parts at it without addressing the cause. Always just saying it's leaks in the pipes.
I have reached out to the manufacturer to find out what about the installation is causing this. Shameful, I know.. Probably $10,000 spend already just on this 1 dry system in under a year solely from the compressor, or as I think it will be proven to be, the installation. /end rant.