Overview

The HDU-100 is a data acquisition and control unit designed for tank level measurement, draft correction, and volume calculation in marine and industrial applications. It features RS-485 and RS-232 communication with MODBUS RTU support, allowing seamless integration with cargo monitoring and alarm systems.

1. Safety Information (p.3-4)

• Electrical Hazards:
  • Power must be isolated before installation or maintenance.
  • Equipment operates at high voltage, requiring extreme caution.
• Electrostatic Discharge (ESD) Precautions:
  • Handle PCBs with care to prevent static damage.
  • Use conductive packaging for PCB storage.
  • DO NOT remove or replace PCBs while power is applied.

2. Storage Before Installation (p.5)

• Store in a dry, covered area to protect from moisture and extreme temperatures.
• Inspect components for physical damage before installation.

3. Features & System Description (p.6-7)

• Tank Level Monitoring: Acquires corrected level and volume data based on draft correction and inclinometer readings.
• Multi-Channel Input & Output:
  • Communicates with AD-80, AD-82, HPI-100, and DA-80 via RS-485 MODBUS RTU.
  • Supports 4-20mA current output for tank level and volume data.
• Alarm System:
  • Dry contact relay output for system fault or communication failure alarms.
  • Buzzer and LED indicators for real-time alerts.
• Draft Correction & Trim Calculation:
  • Uses inclinometer and sensor readings to calculate trim and list correction factors.

4. Technical Specifications (p.6-7)

• Power Supply: 24V DC (0.5A, 10W power consumption)
• Communication Interfaces:
  • 1 x RS-232 port
  • 3 x RS-485 MODBUS RTU ports
• Environmental Conditions:
  • Operating Temperature: -5°C to +55°C
  • Storage Temperature: -20°C to +70°C
  • Humidity Range: 10-90% (Operating), 5-95% (Storage)
• Mechanical Data:
  • Dimensions: 132 × 315 × 30 mm (H × W × D)
  • Weight: 800g
  • Panel Flush Mounting

5. Installation & Wiring (p.7-8)

• Power Supply: 24V DC (18~32V range) with galvanic isolation.
• Communication Wiring:
  • RS-485 for Master-Slave MODBUS RTU communication.
  • RS-232 for external system connections.
• Tank Level Sensor Connection:
  • Configured for cargo tank level input and volume calculation.

6. Communication & MODBUS Protocol (p.8-10)

• MODBUS RTU Communication Settings:
  • Baud Rate: 9600bps
  • Data Bits: 8
  • Stop Bits: 1
  • Parity: None
• MODBUS Data Register Map:
  • Tank Level Data (0x1200 – 0x15FE)
  • Tank Volume Data (0x1600 – 0x17FE)
  • Draft & Inclinometer Values (0x1800 – 0x181E)
  • Gravity Correction Factors (0x1814 – 0x181C)
• MODBUS Example Read Command:
   

   

  01 03 10 00 00 02 C0 CB
  • Retrieves salinity, temperature, or tank level data.

7. Draft & Volume Calculation Functions (p.11-12)

• Draft Calculation Formula:
  • Computes trim correction and list correction based on inclinometer readings.
• Corrected Level Calculation:
  • Applies draft correction for accurate tank volume measurement.
• Volume Calculation:
  • Uses predefined volume table to determine cargo volume.

8. Operation & System Functions (p.12-16)

• LCD Display & Brightness Control:
  • Adjust brightness via F2 (increase) and F5 (decrease) keys.
• Channel Display Navigation:
  • Use F1 and F6 keys to switch between input channels.
• Manual Input Functions:
  • Manual Draft Input: Allows input of trim and list values.
  • Specific Gravity Input: Adjusts sea water, H.F.O., fresh water gravity settings.
• System Settings:
  • Tank Configuration: Set total tank numbers and input types.
  • Communication Addressing: Configure RS-485 slave address.
  • Clock Settings: Adjust date and time.
  • Password Protection: Restricts access to system settings.

9. Alarm System (p.17-18)

• System Alarms:
  • Activated if sensor input exceeds normal range.
  • Displayed via buzzer and LED indicators.
• Communication Alarms:
  • Triggered by RS-232 or RS-485 port failures.
• Dry Contact Output:
  • Used for external alarm relay activation.

10. Revision History (p.19)

• Version R3 (2025.03.03) – Third revision of the technical manual.