Thank's. You're wright but... When you acquire data from several channels, you got a 2D array. If you shift register it and bundle it, you obtain a 3D array. This 3D array is not displayable, isn't ?
I'll try to use a local variable, I don't know yet how to do...
for now, the only way I've found out, is to split the shifted 3D array using a for loop or the "index array" function. It's pretty heavy...