Network
Typical FT NavVision System Diagram
The Local Area Network provides a generic communication path. Ethernet (or the TCP/IP protocol) is the main means of communication and transmission throughout the FT NavVision® system. More precisely: Ethernet takes care of the link between the OWS’s/switches and monitoring units (e.g. sensors).
The monitoring units however are not bound to the TCP/IP protocol for gathering and transmitting data. FT NavVision® supports the additional protocols ModBus, CAN Bus, J1939 and NMEA .
Using Serial-LAN converters, the serial data is ported to the TCP/IP protocol, making the data accessible to all OWSs and LOPs on the network.
Whenever a connection has broken, the event is registered by FT NavVision®. By noticing which piece of equipment is no longer connected, it is able to deduce which network cable is faulty. Power supplies can also be monitored, the relevant information is then written into the logbook. When defined during the initial configuration, any lost connection will generate an alarm. Repaired connections are also detected and written to the system’s log.
Redundancy
The AMCS system offers redundancy. Each individual OWS is able to take over another AMCS function. In case an OWS fails, one of the other OWSs of the system can take over the functions that were being performed. The redundancy is maximized at this moment through 8 AMCS servers in a normal installation. It poses no problem to the system to add 52 client OWS stations or LOPs. The client OWS computers can be used as a fully operational OWS server except that it does not take over redundancy. The LOPs can function as alarm panels with the possibility of extra functionality such as showing the engine environment.
Each AMS server and I/O (PLC) unit is redundantly connected to the Ethernet. Failures in one of the network switches or one of the connection cables will not affect proper functioning of the installation. The operator will be notified of the fault, while still being able to utilize the affected I/O units.
The Ethernet network is based on a ring network topology, ruling out single points of failure as much as possible. When one of the network cables fails, the network data traffic will be redirected to one of the other servers, to be automatically appointed as the master server on that time.
Redundantly available platform systems are connected to different separate PLC’s or I/O units of the system. In case of failure of one of these units, the affected platform system will not be available in the AMCS; however, the back-up platform system shall still be available in the AMCS. In this way, the applicable function is still available, with possibly a reduced capacity.
For vital platform components, on requirement, the OWS provides hardwired (emergency) indications and controls. These indications and controls are directly connected to the appropriate platform component. In case of any failure in the OWS, the vital control and monitoring tasks can still be performed via these direct indications/controls.
Dual & ring
The requirements on board any vessel, as identified by Free Technics, are the following:
• Monitoring & control of equipment
• Central Alarm Management
• Decentralized I/O
These three core requirements need to be addressed with a redundant, fail-safe approach that guarantees safe operation while at sea. The solution found by Free Technics for these requirements are the following:
• Network based I/O
• Failsafe topology through:
•• Ring network
•• Dual Network
Both a ring and a dual network are inherently redundant. Single points of failure are intercepted by the presence of an additional LAN-connection.
As noted above, Ethernet (or the TCP/IP protocol) is the main means of communication and transmission throughout the FT NavVision. More precisely: Ethernet takes care of the link between the OWS’s/switches and the monitoring units (sensors etc.).
The monitoring units however are not bound to the TCP/IP protocol for gathering and transmitting data. The FT NavVision system supports a wide array of additional protocols like ModBus, CANBus, J1939 and more.
Using Serial-LAN converters, the serial data is ported to the TCP/IP protocol, making the data accessible to all OWS’s and LOP’s on the network.
Whenever a connection is broken, the event is registered by the FT NavVision system. By noticing which piece of equipment is no longer connected, FT NavVision is able to deduce which cable is faulty. This information is then written into the logbook. When defined during the initial configuration, any lost connection will throw an alarm. Repaired connections are also detected and written to the system’s log.
