Open Communication Controller

The production system provides subsea communication via an industry proven open communications controller (OCC) which is protocol independent and supports many interface standards such as RS232, RS4xx and Ethernet. 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™).

Usually, communication is through the power lines and is available to all channels and devices installed in the wells or on the seabed. The OCC is protocol independent and transmits each protocol transparently. This allows third party surface applications to directly communicate with their instruments using their native format. The systems architecture will allow any port at the topside to be connected to any port subsea–even Ethernet to serial. The flexibility allows nearly any combination of connectivity between topside and subsea.

The OCC provides the electrical and communications interface to the umbilical power line. Communication between the subsea network and surface equipment can be 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.

The controller is fully customizable and 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 OCC provides multiple layers of communication and diagnosis as illustrated below. The controller performs the functions of a modem, plus control capabilities and diagnostics.

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 queing (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 @ 1 Gb each
• Up to 120 km without repeaters