Problem with ADS1256 board

Hi,

I have the same board in the picture of the first post and I am trying to make this last code work.

I am puzzled a bit by it.
First, I thing that the while(rdy) should really be while (digitalRead(rdy)).
Second, I don't understand the for loop.
It says it wants to read 4 channels, but it iterates only 3 times and I don't know why exactly that choice of values..

Can you make it a bit more explicit?

Thanks!