raman00084
Full Member level 6
I am having problem in measuring inductive load current with acs712(20amps) hall effect sensor, for resistive load it works 99% accurately. I am using pic micr 18f4620 this is my sample code
my idea is simple for 20 ms time(50hz line freq) I am taking 20 samples the finding min and max values
p2p = maxi-mini.
I am getting exact result for resistive loads, my hall effect sensor produces 100mv / amp
For inductive loads such as motors the value shown is In accurate, I also increased the sampling rate for 20ms I took 600 samples but the result is same. for 4 amps motor load my hall effect sensor outputs 400mv measured in multimeter but in pic I am getting in accurate results why so kindly help I want to measure accurate ac current for both inductive and resistive loads.
Regards
Kalyan.
Code C - [expand] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 While(1) { n1 = 0; j = 0; for(int16 i = 0;i<20;i++) { n1++; Table_sinusoide[j] =get_adc_value(3); delay_us(997); j++; } mini = 1023; maxi =1; for(j=0;j<n1;j++) { M=Table_sinusoide[j]; if (mini>M) { mini=M; } if(maxi<M) { maxi=M; } } lcd_gotoxy(1, 1); printf(lcd_putc, "min : %04ld ",mini); lcd_gotoxy(1, 2); printf(lcd_putc, "max : %04ld",maxi); p2p = maxi - mini ; Voltage = (float)p2p * (448/260.1) ; //at 448mv from hall effet sensor I am getting 260.1 p2p value So I fixed this as constants lcd_gotoxy(1, 3); printf(lcd_putc, "p2p: %04ld",p2p); lcd_gotoxy(1, 4); printf(lcd_putc, "voltage:%06.2f ",Voltage);
my idea is simple for 20 ms time(50hz line freq) I am taking 20 samples the finding min and max values
p2p = maxi-mini.
I am getting exact result for resistive loads, my hall effect sensor produces 100mv / amp
For inductive loads such as motors the value shown is In accurate, I also increased the sampling rate for 20ms I took 600 samples but the result is same. for 4 amps motor load my hall effect sensor outputs 400mv measured in multimeter but in pic I am getting in accurate results why so kindly help I want to measure accurate ac current for both inductive and resistive loads.
Regards
Kalyan.
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