i want to use low side current measurement. I connect shunt resistor 1ohm in series with servo. I amplify it using opamp and the output goes to ADC. But during my testing, the ADC reads different2 values although the load is same and the servo is at the same position.
this is my testing. I make my adc read the certain value (x) when the servo reach 90 degree. Then my servo move to 30degree and move back to 90 degree. The value is still x. then it move back to 30 deg and then 90 degree. The value change to y. And when i close the supply. I start from beginning, the value i get can be y value. Why is this happened?
Based on the attachment (page7), i want to make shunt offset adjustment (i make R1, R4, R5 = 1k). I simulate using multisim. I confused with the last equation Vout. It is like not in order and does not include R1. When i simulate in mulsitim, when i change R1, the Vout changes alot. I tried to calculate and it is just can not match the equation. Anyone got any idea about this?
Thanks.
this is my testing. I make my adc read the certain value (x) when the servo reach 90 degree. Then my servo move to 30degree and move back to 90 degree. The value is still x. then it move back to 30 deg and then 90 degree. The value change to y. And when i close the supply. I start from beginning, the value i get can be y value. Why is this happened?
Based on the attachment (page7), i want to make shunt offset adjustment (i make R1, R4, R5 = 1k). I simulate using multisim. I confused with the last equation Vout. It is like not in order and does not include R1. When i simulate in mulsitim, when i change R1, the Vout changes alot. I tried to calculate and it is just can not match the equation. Anyone got any idea about this?
Thanks.