As reported by Nicolas:

-  this morning the control of the laser from the ATK panel was working fine (enable amplier output)

- this afternoon at about 2pm it was noticed that no communication was obtained with the laser thourgh ATK panel, suggesting something wrong with ElliOOs. 

So, I went to optical room and noticed that:

- ElliOOs was frozen on the vizualisation panels (Host PC). I first closed ElliOOs on that machine and restarted it. The connection screen was frozen (gray-ed).

- thus connected to remote PC (embarqué) through ssh and observed that ElliOOsd process was not running.

I decided to "take my chance" and simply reboot the remote PC using linux in-line command. The Host ElliOOs panel went back working so that I could connect with usual username. However the window disappeared preventing any control of the laser from the Host machine. This is strange and reamains unexplained to me. To be investigated by Viktor when he is back ?

However, the ATK panel is working again, allowing laser control from the control room.