iSSR
intelligent Solid State Relay
The iSSR is a compact, intelligent solid state relay designed for PBOF subsea operation at depths up to 6,000 meters. It features a 60A AC blocking switch rated at 800V nominal (1000V peak) with built-in soft start, making it ideal for subsea power distribution systems.
A switchable 50mA constant-current bypass circuit pre-charges load capacitance for safe power-up sequencing. Input-output isolation is 1000V minimum. The unit operates on 5-36V DC and supports Ethernet, RS-232, RS-485, and CAN bus communications. Multiple units can be daisy-chained off a single power and control connection, enabling scalable power distribution architectures.
2G Engineering is an AS9100 certified organization.
Operating Conditions
Pressure
Rated for PBOF operation at depths exceeding 6,000 meters (10,000 psi).
Temperature
Operating temperature range: -20° C to 65° C
Storage temperature range: -30° C to 85° C
Environment
Designed for pressure-balanced oil-filled (PBOF) operation. Suitable for fully submerged subsea environments and topside industrial applications.
Power Ratings & Soft Start
Switching Capacity
60A continuous current with 800V nominal switching voltage (1000V peak). AC blocking configuration prevents reverse current flow.
Built-in Soft Start
Integrated 50mA constant-current bypass circuit safely pre-charges load capacitance before main switch engagement. This prevents damaging inrush currents that can trip protection systems or damage downstream electronics.
The soft start function is independently controllable via the communications interface, allowing automated power-up sequencing in complex subsea systems.
1000V Galvanic Isolation
Minimum 1000V input-output isolation protects sensitive control electronics from high-voltage power buses. The unit trigger and operating voltage range is 5-36V DC, compatible with standard subsea control voltages.
Daisy-Chain Architecture
Multiple iSSR units can be connected in series off a single power and control bus, dramatically reducing wiring complexity in multi-channel power distribution systems.
Each unit is individually addressable over Modbus protocol and can be independently commanded to open, close, or engage soft start. This allows a single host controller to manage an entire power distribution tree from a central communications bus.
The daisy-chain connector uses a compact flat-flex cable (Parlex PN 100R5-102B or equivalent) to link units with minimal space overhead. The architecture supports both point-to-point and multi-drop configurations.
Status LEDs
Four status LEDs provide at-a-glance indication of unit state: ON, Pre-Charge active, Data RX/TX, VIN presence, and GND connection. Visible even in low-light subsea conditions through oil-filled housings.
Communication Interfaces
Ethernet, RS-232, RS-485, and CAN bus interfaces are all available. The main comms connector provides power and control on a single 6-pin connection. USB-C port enables direct configuration and firmware updates.
Modbus Protocol
All unit functions are accessible via standard Modbus protocol. Read switch state, control soft start timing, monitor diagnostics, and command switching operations. Compatible with standard industrial control systems and PLCs.
Rugged Durable Design
2G Engineering has been building subsea electronics since 2008. The iSSR is engineered for the most demanding subsea and industrial environments. The compact form factor (57mm x 44mm x 26mm) allows integration into tight pressure housings while the screw terminal power connections (1/4-28 UNF) ensure reliable high-current operation under vibration and pressure cycling.
The unit is designed for pressure-balanced, oil-filled (PBOF) operation at depths exceeding 6,000 meters. All components are selected for wide temperature range operation and long-term reliability in harsh environments. M4/#10 mounting screws on each end provide secure mechanical attachment.
Documentation & Support
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