Propeller Pitch and Engine Load Control Implementation
Wärtsilä, a leading international supplier of marine engines and engine management systems, was approached by Sea Harvest to upgrade the engine management system on the ocean-going trawler, Miriam Makeba. The existing system had become obsolete, with no spare parts available. Since the engine itself remained in good working order, only the control system required an upgrade.
Designing an Integrated Control System
Developing a propeller pitch control system is closely tied to engine load control. Both must be seamlessly integrated to ensure an efficient closed-loop system. Several key factors were considered when designing the new system:
- Whether to implement a dedicated purpose-built system or an open-architecture alternative (PLC with HMI/SCADA)
- The operating environment for the PLC and HMI, ensuring long maintenance-free periods
- The mathematical processing power of the PLC
- The cost-effectiveness of large-scale data acquisition using a PLC and HMI
After careful evaluation, the LS Industrial Systems XGI PLC was selected for its processing power, reliability, and flexibility.
Advanced SCADA Interface with LSIS InfoU
For data-logging and advanced graphics, the InfoU SCADA package (also from LS Industrial Systems) was chosen. This software allowed for:
- Quick graphical user interface (GUI) development
- Installation on a Nagasaki industrial touch screen PC
- Real-time control value monitoring
- Comparison with pre-calibrated values stored in the PLC
The GUI was designed for easy recalibration—if adjustments are needed during the system’s lifetime, they can be made instantly at the touch of a button.
Real-Time Engine Load Monitoring
The engine load is continuously monitored by plotting the real-time throttle position against the pre-charted 10-point maximum power curve of the engine. This enables the system to:
- Calculate rate of change of propeller pitch and automatic load reduction
- Prevent engine overload—if the real-time load exceeds 100%, the system automatically reduces the propeller pitch and alerts the operator
- Detect rough sea conditions and adjust the propeller pitch accordingly
Additionally, the PLC controls the start/stop sequences and automatic shutdown of the engine, which are clearly displayed on the GUI—minimizing operator intervention.
Comprehensive Engine Monitoring & Alarm System
The system is designed for complete engine condition monitoring, including:
- Exhaust temperatures
- Water and fuel pressures
- Temperature sensors
Set points are constantly monitored by the PLC, and alarms are displayed across all SCADA screens. Alarm events are also logged, ensuring that maintenance personnel can quickly diagnose issues when the vessel returns to port.
For added security and accountability:
- Alarm events can only be cleared by a supervisor
- A password-controlled reset ensures proper maintenance tracking
Innovative Marine Automation for Maximum Efficiency
By integrating LS Industrial Systems XGI PLC with InfoU SCADA, this upgrade enhances vessel efficiency, safety, and reliability. With automated monitoring, real-time adjustments, and minimized human intervention, the Miriam Makeba now operates with a state-of-the-art engine control system built for performance and longevity.