Inputs/Outputs with the X1 Front End Interlock

The relay contacts that the X-1A interlock controller provides to the X1 front end interlock are:

EMNO	Enable Mask (normally open)
EMNC	Enable Mask (normally closed)
EMC	Enable Mask (common)
	A set of relay contacts that will form a closed circuit between EMNO and EMC and an open circuit between EMNC and EMC ONLY when it is safe for the X-1A and X-1B beamlines to accept beam (as described earlier). It is expected that when this circuit opens, the photon mask should immediately be shut by the X1 front end interlock.

AACNO	Branch Line A active (normally open)
AACC	Branch Line A active (common)
	A set of relay contacts that will form a closed circuit when the X-1A branch line is in a configuration for taking beam (i.e., the X-1A deflection mirror is in the beam). For Operations Coordinator information.

BACNO	Branch Line B active (normally open)
BACC	Branch Line B active (common)
	A set of relay contacts that will form a closed circuit when the X-1B branch line is in a configuration for taking beam. For Operations Coordinator information.

The relay contacts that the X-1A beamline interlock receives from the X1 front end interlock are:

MONO	Mask open (normally open)
MOC	Mask open (common)
	A set of relay contacts that are closed only when the mask is not closed.

FEVNO	Front End Vacuum (normally open)
FEVC	Front End Vacuum (common)
	A set of relay contacts that are closed only when the pressure in the downstream end of the front end vacuum system (upstream of the first X1 beamline-controlled valve) is below the set point. When the FEVNO and FEVC relay contacts become an open circuit (i.e. front end pressure rises), we will close V1 and, of course, open the Enable Mask circuit contacts EMNO and EMC.

ASNO	Automatic Shutter (normally open)
ASC	Automatic Shutter (common)
	A set of relay contacts that are closed only when the X1 safety shutter is in the automatic mode. When the X1 front end interlock has the key turned to put it in automatic shutter mode, the shutter will be opened automatically by the Operations Coordinator acting in the control room after every fill.