Yokogawa, CMZ900 Gyro Compass ( WITHOUT GYRO SPHERE )

The Yokogawa CMZ900 Gyro Compass is a highly regarded and widely deployed true heading sensor system in the marine industry. Known for its reliability, compact design, and adherence to international standards, it provides critical heading and rate-of-turn data for accurate navigation, autopilot systems, radar stabilization, and other bridge equipment.

Core Function and Purpose:

The fundamental purpose of the CMZ900 is to determine and maintain a vessel’s true heading by utilizing a fast-spinning rotor that is influenced by gravity and the Earth’s rotation. This provides a stable and accurate reference, crucial for safe and efficient maritime operations, especially in situations where magnetic compasses are less reliable due to magnetic interference or proximity to the Earth’s magnetic poles

Technical Specification

Performance:

Accuracy:
- Static: $\pm 0.2 5^{\circ} \times sec (latitude)$
- Dynamic: $\pm 0.7 5^{\circ} \times sec (latitude)$
Settling Time: Within 5 hours (operational state reached in approximately 2 hours)
Follow-up Accuracy: $\leq 0. 1^{\circ}$
Maximum Follow-up Speed: $3 0^{\circ} / s$
Permissible Roll and Pitch Angle: $\pm 4 0^{\circ}$
Permissible Vibration:
- 0 to 8.3 Hz: $\leq 3 mm P-P$
- 8.3 to 25 Hz: $\leq 0.35 mm P-P$
- 25 to 50 Hz: $\leq 0.1 mm P-P$
Permissible Acceleration: $\leq 0.5 G$ (for 0.5 seconds or less)

Power Supply:

Main Power Supply: 24 VDC (Range: 20 VDC to 30 VDC)
Optional AC Adapter (MKS070 for CMZ900-B2/S, MKS071 for CMZ900-D):
- 100/110/115/220 VAC, 50/60 Hz, single-phase (provides power to the system, with 24VDC as backup)
Power Consumption (approximate, varies slightly by model and number of repeaters):
- DC Drive (Operating): Approx. 2.3A – 3.5A (plus 0.35A per repeater compass)
- DC Drive (Starting): Approx. 3.5A – 4.7A (plus 0.35A per repeater compass)
- AC Drive (Operating): Approx. 90VA – 100VA (plus 12VA per repeater compass)
- AC Drive (Starting): Approx. 125VA (plus 12VA per repeater compass)

Data Interfaces (Inputs):

Ship’s Speed & Latitude: 1 circuit, IEC 61162-1 (NMEA 0183) for automatic speed error correction. (Also 200 pulses/nm for speed input)
External Heading Data (Backup): 1 circuit, IEC 61162-1 (NMEA 0183)
Buzzer Stop: 1 contact circuit
Steering Mode: 1 contact circuit
External Heading Sensor Selection: 1 contact circuit

Data Interfaces (Outputs):

Serial Data (NMEA 0183):
- Multiple circuits (typically 3 or more).
- IEC 61162-1 (4800 bps) and/or IEC 61162-2 (selectable high-speed transmission) for Heading (HDT, HDG), Rate of Turn (ROT), etc.
Repeater Compass Drives:
- Up to 8 circuits (depending on model/configuration).
- RS422 (9600bps) for digital repeaters.
Stepper Outputs: 1 circuit (3-bit gray code, 24VDC or 35VDC option)
Analog Rate of Turn (ROT): Up to 3 circuits (0V to 5VDC output)
Analog Heading & Quadrant: 1 circuit each (0V to 5VDC output)
Alarms (Contact Outputs):
- Master Compass Failure Alarm: 1 circuit (open/closed selectable)
- DC Power Failure Alarm: 1 circuit (open/closed selectable)
- System Status/Running Status
BAMS (Bridge Alert Management System) Output: IEC 61162-1 serial signal (4800bps) for alert notices/lists (e.g., ALF, ALC, ARC, HBT).

Physical and Environmental:

Dimensions (Approximate, Master Compass MKM026):
- Height: 420 mm
- Width: 420 mm
- Depth: 502 mm
Weight (Approximate, Master Compass MKM026): 43 kg (Control box and AC adapter add weight to the total system)
Operating Temperature:
- Master Compass: $- 1 0^{\circ} C$ to $+ 5 0^{\circ} C$
- Other Protected Equipment (e.g., Control Box): $- 1 5^{\circ} C$ to $+ 5 5^{\circ} C$
Protection Grade: Varies by component, but typically designed for protected bridge environments.
Magnetic Clearance: (Not typically specified as it is a gyrocompass)