I am looking for some assistance in setting up a current sensor with an arduino due.
I would like to use this part (100A PN) http://www.lem.com/docs/products/hais_e_rev11.pdf
From what I understand I will supply the sensor with 5V from the DUE.
What I am unsure about is the VREF and how to convert the readings to suit the 3.3V range of the analog pins on the Due.
From what I understand VREF can be both a driven input or an output??
When not driven VREF is an output voltage of = 2.5V+/- 0.025??
The voltage output of the sensor will be equal to VREF +/- (0.0625*I/100)
So Vout max (300A) = 4.375V and Vout min (-300A) = 0.625V
As this exceeds the maximum voltage I can put into the analog pins of the due then I think I need some sort of potential divider to lower the Vout max to 3.3V at 300A.
The problem I have is I can not seem to figure out what the output current of the sensor is. Do I use the output internal resistance value of 5 Ohms? In which case my output current is 0.125A to 0.875A and then work out my divider resistors to give a range of 3.3V to 0V?
Also is my assumption about VREF correct? Do I need to just measure it to check it is 2.5V and use it in my calculation of Vout or do I need to supply VREF in some way from the Due?
Any help would be much appreciated as I think I have taken it as far as my own knowledge can!