Overview

The OVMS-50 is an advanced Oxygen Vapour Monitoring System developed by HANLA IMS Co., Ltd. This device is specifically designed to monitor oxygen concentration and vapour pressure within inert gas systems on marine vessels. The OVMS-50 supports up to five channels of analog input, providing high-accuracy measurements and robust alarm management features for reliable safety monitoring.

1. Key Features (p.9)

• Supports 5 channels of analog 4~20mA input signals, with conversion to digital display via LCD.
• Designed for Oxygen Vapour Emission Control System monitoring.
• High-accuracy 24-bit A/D conversion increases measurement reliability.
• User-defined scaling of inputs and output via MODBUS communication protocol.
• Panel-mountable with robust construction using fiberglass reinforced Noryl.

2. System Specifications (p.9)

3. Safety Information (p.5)

• Electrical Hazard Warning: Ensure power is isolated during installation or maintenance.
• Anti-static Precautions: Handle PCBs with appropriate grounding techniques to prevent ESD damage.
• Installation Permits: Required prior to performing any work on the system.

4. Alarms and Indicators (p.10-11)

• Oxygen High Alarm: Triggers at 8% O2 (preset). Sensor breaks activate fail-safe relay and LED alerts.
• Non-Flow Alarm: Monitors sampling tube blockage. Displays ON/OFF status and triggers Fail LED if input drops below 94.
• Vapour Pressure Alarm: Alarms triggered for low pressure at 0.01 bar and high pressure at 0.126 bar. Displays UNDER/OVER messages for sensor anomalies.
• Alarm Accept & Buzzer Controls:
  • Alarm Accept button silences alarms and resets relays.
  • Buzzer Stop button mutes the buzzer without resetting the alarm LED.

5. Connections & Power (p.12-13)

• Sensor Inputs: 4~20mA and contact signals are accepted through designated terminals.
• Power Connection: AC input between terminals 13 and 14, with frame grounding on terminal 15.
• Alarm Outputs: Each channel provides potential-free bi-directional contact outputs for external alarms.

6. Display and User Interface (p.14-15)

• Main Display: Shows channel number, process value (PV), unit, and status.
• Status Indicators:
  • OK: Normal operation
  • A1/A2: Alarm conditions
  • F!!: Sensor Fail
• Main Menu Options: Channel selection, lamp test, password setup, communication address, and COM settings.

7. Functions and Configuration (p.15-22)

• Input Types: Supports 4~20mA current and contact signals.
• Scaling: User-defined scaling of PV for oxygen, vapour pressure, and non-flow detection.
• Alarm Type Selection: Multiple alarm logic configurations (HH, H, L, LL) with NO/NC options.
• Buzzer Settings: Configurable for alarm activation.
• Alarm Dead Band: Prevents chattering near alarm thresholds.
• Offset Function: Adjusts display values to compensate for installation variances.
• Display Type Options: Limit, RAW, or UNDER/OVER display modes.

8. Communication Protocol (p.23-28)

• MODBUS Protocol Support
  • Slave address range: 0x11~0x1F
  • Baud rates: 1,200 ~ 230,400 bps
  • Commands:
    • Read raw data (integer/float) from single or multiple channels
    • Read/write channel coefficients
• Communication Parameters:
  • 8 Data bits, 1 Stop bit, No Parity
  • Channel data accessible in both long integer and IEEE754 float types.

9. Calibration & Maintenance (p.20-22, 46-47)

• Channel Calibration:
  • Zero and Span adjustments for 4~20mA inputs.
  • Contact signal calibration ensures accurate PV readings.
• Maintenance:
  • Perform regular inspections on connectors, sensors, and PCBs.
  • Ensure proper storage in dry, sheltered environments before installation.

Revision History (p.29)

• Revision R22: Format revision dated 2025.03.15.