Hi all,
I have two questions about connecting sensors to the Flex-Full Board.

1) I have a sensor which has got an output 0-5V. Which is the best way to connect it to the Flex which has got the Vref levels 0-3.3V ?

2) I have another sensor which has three pins +12V, OUT (0-5V), GND. From the Flex I have only the possibility to have 3.3V or 5V as output power supply. If I use an external power supply for the sensor I think I'll lose the ground reference and than I won't have a correct measure from the sensor ? How could I solve it ?

Thanks in advance,
Pasquale.

Hi Pasquale!

About the following one:


1) I have a sensor which has got an output 0-5V. Which is the best way to connect it to the Flex which has got the Vref levels 0-3.3V ?


check the pins you want to connect on the dspic datasheet. Most of the dsPIC pins accept a 5V input...

ciao,

PJ

Hi,
I've checked. The problem is the only digital input pins can accept 5V. Unfortunatly not analog input pins.


Any order informatiot about my post ?


Thank you,
Pasquale.

You're right, analog inputs accept only voltages in the 0-3V3 range.

The faster solution is a couple of resistors in order to do a partition. Better solutions are possible with buffers, OA with gain set to 2/3 and so on... It depends from your sensor.

Thank you very much. What about the second one :

2) I have another sensor which has three pins +12V, OUT (0-5V), GND. From the Flex I have only the possibility to have 3.3V or 5V as output power supply. If I use an external power supply for the sensor I think I'll lose the ground reference and than I won't have a correct measure from the sensor ?

You have 2 possibilities:

1. You use an external 12V power supply and connect the 2 Ground.


2. You power the Flex board with a 12V supply and use the Vout line for the sensor power supply.

Thr first one is better in term of quality, while the second one is easier because it uses only 1 powre supply.