Primary Nodes

Primary node PN1C connected to the Endurance Oregon Offshore site (600 m), with the protective doors closed.
Photo Credit: NSF-OOI/UW/CSSF, Dive 1747, V14

There are 7 Primary Nodes on the Regional Cabled Array. Each Primary Node provides 8 kW of power, 10 GbE bandwidth, and pulse per second timing at ocean depths to ~2900 meters and at distances >500 km offshore. Five science ports (1 GbE, 375 V), two high bandwidth science ports (10 GbE, 375 V) and two backbone expansion ports (10 kV) provide significant expansion capabilities through connection of secondary extension cables.

An octopus hanging out next to primary node PN3A at Axial Base, 2600 meters deep.
Photo Credit: NSF-OOI/UW/CSSF, Dive 1742, V14

Six of the seven Primary Nodes house two main assemblies: the Base Interface Assembly (BIA) and the Science Interface Assembly (SIA). The BIA is hardwired into the Primary Node assembly and to the backbone cable, requiring installation and recovery with an industry cable ship. The BIA houses Medium Voltage Converters (MVC’s) that convert 10 kVDC to 375 VDC to power Low-Voltage, Low-Power, and Medium Power Junction Boxes. The BIA’s also contain two backbone expansion ports (10 kV). The SIA’s are wet-mated within the Primary Node assembly allowing deployment and recovery by remotely operated vehicle for ease in maintenance and upgrades. Each SIA houses five wet-matable science ports with 1 GbE and 375 V and two high-bandwidth ports (10 GbE, 375V) with wetmate connectors. The Primary Node at Mid-Plate houses a BIA – future expansion will require the inclusion of an SIA. All Primary infrastructure has an expected operational life of at least 25 years.