Total sensor Analog/Digital

Hi.

I have 30 analog inputs and 10 digital inputs, in two arduino mega by ethernet shield.

I need save in real time and historical, and know the maximun time in days for historical.

I dont know nothing about the maximun of sensors and the price o license for this…

Thanks for all.

what do you mean by this?

you can add n number of sensors and devices. cayenne is free is to use.