I saw a question regarding the "clocks" which I think I can provide some information. This is more than just a 'clock':
The passage time of the bunches actually depends upon many parameters like proton energy, ring diameter, etc. It is therefore easier to let the protons spin at their own rate and then synchronize the whole collider on them : The beam control center then sends a signal to the detector teams so they can synchronize their own experiment on the beam: this is called "external clock" state.
Of course, when there is no beam the experiments are either OFF or they can pretend there is a beam but they have to simulate this signal themself: this is just a stand by mode called "internal clock".
BC1 is the beam clock signal for the beam 1, while BC2 is for the beam 2. There is also a combined clock signal that will be used when both beams are present and ... colliding.