hi, i wanna measure the current flow coming from a hall effect sensor to the tesla meter so that taking that current and find the magnetic field by using formula on pc program so my idea is as the following
i put a small shunt resistor in series with the sensor so that i measure the voltage drop across the 1ohm resistor and then find the current by ohm law an so on but trouble begins to show up
it is supposed that the current flow will be at maximum is 10A and because the magnetic field has 2 directions so it would be -10A or +10A so the limits for the voltage measurements is -10v or +10v
and as we know
1. pic can't handle voltage greater than the range 0v to +5v
2. pic can't handle negative voltage
i put a design to a circuit it suppose to convert negative voltage to positive an in the same time do a voltage level shift from range (-10v~0v) or range (0v~+10v) to to the range (0v~+5v) so that the pic can handle it
here is my design
http://lookpic.com/c1/i2/2113/pcMlkWJ3.jpeg
or
http://img269.imageshack.us/img269/7452/voltagelevelshift.jpg
and here is the design file
http://www.mediafire.com/?mwiuk2puz6u469o
at general what is the best method to measure a dc positive or negative current in range of -/+ 10A using pic ?
i put a small shunt resistor in series with the sensor so that i measure the voltage drop across the 1ohm resistor and then find the current by ohm law an so on but trouble begins to show up
it is supposed that the current flow will be at maximum is 10A and because the magnetic field has 2 directions so it would be -10A or +10A so the limits for the voltage measurements is -10v or +10v
and as we know
1. pic can't handle voltage greater than the range 0v to +5v
2. pic can't handle negative voltage
i put a design to a circuit it suppose to convert negative voltage to positive an in the same time do a voltage level shift from range (-10v~0v) or range (0v~+10v) to to the range (0v~+5v) so that the pic can handle it
here is my design
http://lookpic.com/c1/i2/2113/pcMlkWJ3.jpeg
or
http://img269.imageshack.us/img269/7452/voltagelevelshift.jpg
and here is the design file
http://www.mediafire.com/?mwiuk2puz6u469o
at general what is the best method to measure a dc positive or negative current in range of -/+ 10A using pic ?