The on board readout electronic has 32 independent channels, one for
each column of the array. It is based on DC amplifiers followed by
sample and hold circuit. An analog multiplexer is used to read each
line and to encode the signal on 4096 levels. A programmable offset is
applied before the analog to digital converter, and the gain of the
chain can be selected among the 3 factors 
1, 2 or
4, to allow for a good sampling of the noise in low flux
conditions, and to take advantage of the whole dynamic range. The
offset is automatically set, and the observer must choose the gain; in
normal conditions, a gain 2 should be selected, providing 120
e
/ADU and a good sampling of the 1.5 ADU rms of the readout noise
over the whole linear range of the array. With this gain the dynamics
of the system is limited by the analog to digital converter to
5
e/px. In case of a higher signal, a gain
1 should be selected.