  In this paper, the DSSC safety-interlock system is introduced. It is designed
to keep the DSSC mega-pixel camera in a safe-state. The system is composed of
four inter-communicating sub-systems referred here as a master SIB
(safety-interlock board) and three partner SIBs. Each SIB monitors and
processes 75 temperature sensors mainly located in the focal plane and also
distributed inside the camera-head electronics. It monitors the signals from
two pressure sensors, one humidity sensor as well as the connectivity to
sixteen low-voltage and two high-voltage cables. The master SIB supervises the
signals to and from external equipments like the cooling system, pressure
gauge, power crates and status information from experimental environment. SIB
is an 8-layer printed-circuit board (PCB) with a micro-controller sitting on
top as its central processing unit. A decision-matrix software reads the sensor
status continuously and determines whether the camera is in a safe state or
not. All error and warnings flags are sent to the detector control software
framework and the end user directly. These flags are also stored every 100 ms
together with the image data. The full SIB sensor data is sent to the back end
for offline analysis. A shutdown sequence is initiated by SIB in case of a
critical failure. The safety-interlock philosophy, hardware design, and
software architecture along with test results will be presented.
