This production system provides subsea communication using an industry-proven open communications controller (OCC). The OCC is protocol-independent and supports many interface standards such as RS232, RS4xx and Ethernet. The system architecture allows any port at the topside to be connected to any port subsea—even Ethernet-to-serial—for enhanced flexibility.

The OCC provides the electrical and communications interface to the umbilical power line. Communication between the subsea network and surface equipment can be achieved through power lines or optical cable using IWIS/RS422 or Ethernet. Interfaces to subsea devices include fieldbus (Modbus, PROFIBUS and CANbus), intelligent information systems (IIS), optical sensors, custom RS485/RS422/RS232, and vendor-specified interfaces.

The controller is fully customizable; user-specific features can be embedded into the firmware. It contains a built-in web server for setting parameters, diagnostics, and firmware upgrades. A single topside unit can communicate with multiple subsea units, all sharing a single power cable for communication (multi-drop).

The system also complies with other open standards such as intelligent well interface standardization (IWIS), transmission control protocol/internet protocol (TCP/IP), Modbus^®, Modbus TCP and production markup language (ProdML™).

Retrofit Capability

The open architecture of the OCC enables the system to share an existing subsea network. In most cases this allows installation of new technology instrumentation without having to replace the existing subsea infrastructure.

OCC Power Line Benefits/Features

• High speed–up to 390 kbps
• Mean time between failures > 25 years
• Power handling up to 500 VAC/1000 VDC
• Galvanically isolated dual RS422/RS485 and Ethernet ports
• IWIS-compliant, providing full Ethernet/IP transparency from topside to subsea
• Compact and versatile covering all main communication topologies including multi-drop
• Easy configuration using web browsers and configuration wizards
• Local I/O capabilities
• Full Modbus TCP/remote terminal unit (RTU) support

OCC Power Line Specifications

• Communication distances up to 100 km
• Selectable power line frequency from 50 to 630 kHz
• Electrical interfaces topside and subsea-RS232, RS4xx and Ethernet
• Auto recovery of subsea communications
• Transparent communications
• Supports Modbus, PROFIBUS and IWIS standards

OCC Fiber-Optic Benefits/Features

• Real-time performance using priority queuing (QoS and CoS), IGMP filtering
• Supports fault tolerant loops or redundant rings using rapid spanning tree protocol (RSTP)
• SNMP version 3 for secure (authenticated encrypted) SNMP messaging

OCC Fiber-Optic Specifications

• Up to two uplinks at 1 Gb each
• Up to 120km without repeaters