The Cameron Mark III MUX BOP control system consists of three major components: the MUX section, subsea electronic module (SEM), and the surface control panel.

The Mark III control system MUX uses pressure-compensated dielectric-filled chambers in the solenoids and transducers, rather than one-atmospheric chambers. Its modular design of the solenoid chambers, transducer chambers, and pilot accumulators provides additional barriers to sea water. It is engineered for simplified maintenance of the solenoid valves. Rechargeable batteries for automatic mode function/deadman system reduces battery replacement.

The SEM has fewer cards and less wiring, providing increased functions in a smaller size. The electronics have been repackaged to increase efficiency of heat dissipation. The SEM uses computerized driver modules, eliminating the pie connectors seen in the Mark I and Mark II.

The control panel replaces hard wire push-button panels with electronic, full-color touch-screens. Multiple screens display more comprehensive information, including functions and alarms. Updated programming with enhanced graphics allows more intuitive, user-friendly visual indicators. An upgraded communication system, utilizing Ethernet technology via fiber optics, provides more robust network management.


  • Touch-screen control panels with enhanced graphics and upgraded communication system
  • SEM has fewer cards and less wiring and utilizes computerized driver modules
  • Solenoids and transducers have pressure compensated dielectric-filled chambers
  • Power and communication signal transmits to both the SEM and Riser Control Box (RCB) simultaneously and independently