Sperry Marine, Navipilot 4000 Steering Control Unit Type 4961

The Sperry Marine Navipilot 4000 Steering Control Unit (SCU) Type 4961 is the central processing unit for the NAVIPILOT 4000 series autopilots. It features self-tuning adaptive heading control, continuously optimizing steering performance based on vessel and environmental conditions for fuel efficiency. It utilizes a CAN (Control Area Network) interface for simplified system integration and supports multiple steering modes including AUTO, NAV, TRACK, and manual control. The Type 4961 manages all system inputs and outputs, providing comprehensive steering control and various interfaces for navigation sensors and external systems.

Technical Specification

Electrical Specifications:

Power Requirements:
- Voltage: 24 VDC (ranging from 18 V to 36 V)
- Max. Ripple Content: 4 V peak-to-peak (pp), with extreme values not exceeding 36 V or falling below 18 V.
- Power Consumption: 10 W max.
- Protection: Built-in reverse polarity protection.
Inputs:
- Gyrocompass Heading Interfaces: Two RS 422 connections.
- Magnetic Compass Interfaces: IEC 61162-1, sine/cosine.
- NAV/TRACK Interface: Serial interface for track steering via Sperry Marine’s VisionMaster FT ECDIS or standard waypoint steering with position receivers (NMEA 0183, sentence selectable).
- Speed Input: 200 pulses per nautical mile (p/nm) or IEC 61162-1 (NMEA 0183).
- Rudder Angle Feedback Signal: ±10 V (corresponding to ±120° max selectable rudder angle) from a 2 kΩ potentiometer.
- External Steering System Input: ±10 V (corresponding to ±120° max rudder angle).
- Fluxgate for Magnetic Compass: Sine/cosine (Sperry Marine product).
- 180° Turn Command: Port and starboard.
- Gyro/Magnetic Selection: For choosing the heading source.
- Override Status: Input for override mode.
- Mute: Input for muting alarms.
- Status Signals: AUTO, NFU, Helm, Remote, Ext. System.
- Heading: IEC 61162-1 (HEHDT at 10 Hz for gyro, HCHDT or HCHDM or HCHDG at 10 Hz for magnetic).
- Navigation System Data (NSD): At 1 Hz.
- Central Alarm: IEC 61162-1 bidirectional input/output.
- Voyage Data Recorder (VDR): RS 422 9600 bps.
Outputs:
- Analogue Output: For thruster control, rudder propellers, and water jets (proportional rudder order to proportional rudder error, ±10V DC, max. 20 mA or 4-20 mA, optional).
- DC Solenoid Valves: Two for port, two for starboard (solid-state relays, plus or minus switching).
  - Voltage: 12 VDC to 110 VDC.
  - Rating: 2.0 A max.
- AC Solenoid Valves (Optional): Two for port, two for starboard (solid-state relays).
  - Voltage: 24 VAC to 230 VAC.
  - Rating: 1.0 A max.
- CAN: In accordance with IEC 61162-3 for remote control and display units and connection to NAVIGUIDE 4000 manual steering system.
- Status and Alarm Outputs:
  - System Alarm: Potential-free contacts.
  - Off Course Alarm: Potential-free contacts (2 A maximum current).
  - Override Alarm: Potential-free contacts (250 V maximum voltage).
  - Gyro/Mag Status: Potential-free contacts (max. 4 outputs selectable).
  - Ext. System Status: Potential-free contacts.
  - Deadman’s Control: Potential-free contacts.
  - Mute: Potential-free contacts.
  - Power Failure Alarm: Primary and backup supply, potential-free contacts.

Mechanical Specifications:

Dimensions (H x W x D): Approximately 151 mm x 392 mm x 425 mm.
Weight: Approximately 3 kg.
Cable Connections: Screw-down terminals.
Protection Grade (Installed): IP32 to DIN 40050.
Magnetic Clearance: 0.4 m (minimum safe distance to a standard magnetic compass).

Environmental Specifications:

Ambient Temperature Range:
- Operation: -15° C to +55° C.
- Storage: -25° C to +70° C.
Environmental Testing: To EN 60945 (IEC 945 + A1).