Electronics Overview of the Subsea Control Module

The subsea electronics module (SEM) has been designed to be surface removable and replaceable without the need to disturb the module’s hydraulics chamber. It houses power, communications, control and third party interface electronics. The housing provides a one-atmosphere dry nitrogen purged environment located within the main SCM housing. Proprietary penetrators provide connection to the SCM and external tree instrumentation.

Communications between surface and subsea are by means of a redundant intelligent well interface standardization (IWIS) point-to-point protocol (PPP) compliant power line carrier modem providing Ethernet, RS232 and RS4XX with open protocol connectivity. Communications can be implemented to suit comms-on-power, separate comms-and-power or fiber optic that is dependent on client and application requirements. A configurable frequency band of operation (50 to 690 kHz) enables integration and co-existence with other legacy power-line modems to develop existing system extensions of control and/or data devices. The system bandwidth range is 1 to 390 kbps available; dependant upon umbilical cable characteristics.

The SEM provides control and data monitoring via a dedicated embedded processor with scalable and configurable input/output channel configurations to suit client and application requirements. Communications for data retrieval or control commands with the SEM processor is by Modbus® RTU protocol. In addition, the SEM incorporates internal diagnostic monitoring for internal power supplies, environmental, processor status and communications.

Extensive system configuration and diagnostic tools and displays are available to the users via the topside MCS workstation.

Note: User levels of security access are applied to ensure the safety and ease of use for the system.