Hello,
Has anyone ever used one of these ZMPT101B current transformers for measuring AC voltage with a microcontroller?
I’m struggling to get any linearity with it at all and I can’t understand why.
Here is what I’m doing:
I’m using a Variac which can produce voltages from 1vac – 330vac
If I supply the module with a steady 5.00vdc, the output pin reads 2.500v.
The output voltage doesn’t start decreasing until about 90vac input.
At 330vac I get 2.350 volts on the output of the module.
330vac – 90vac = 240vac. 240vac is the range it can measure.
2.500vdc-2.350vdc = 0.15vdc. This represents the output voltage of the module measuring voltages from 90vac to 330vac.
0.15 / 240 = 0.000625 Per Volt.
So, if I wanted to measure 200vac, my voltage output on the module should be 200*0.000625 = 0.125. 2.500-0.125 = 2.375vdc.
If I put the above into practise, at 200vac my output voltage is way off. Even if I adjust the numbers and try and measure different voltage ranges, I can’t seem to get any linearity at all.
I know I'm doing something wrong.
Is my approach all wrong? How would you go about implementing this sensor differently?
Any help is hugely appreciated.
Has anyone ever used one of these ZMPT101B current transformers for measuring AC voltage with a microcontroller?
I’m struggling to get any linearity with it at all and I can’t understand why.
Here is what I’m doing:
I’m using a Variac which can produce voltages from 1vac – 330vac
If I supply the module with a steady 5.00vdc, the output pin reads 2.500v.
The output voltage doesn’t start decreasing until about 90vac input.
At 330vac I get 2.350 volts on the output of the module.
330vac – 90vac = 240vac. 240vac is the range it can measure.
2.500vdc-2.350vdc = 0.15vdc. This represents the output voltage of the module measuring voltages from 90vac to 330vac.
0.15 / 240 = 0.000625 Per Volt.
So, if I wanted to measure 200vac, my voltage output on the module should be 200*0.000625 = 0.125. 2.500-0.125 = 2.375vdc.
If I put the above into practise, at 200vac my output voltage is way off. Even if I adjust the numbers and try and measure different voltage ranges, I can’t seem to get any linearity at all.
I know I'm doing something wrong.
Is my approach all wrong? How would you go about implementing this sensor differently?
Any help is hugely appreciated.