Application of GE Fanuc PLC in Ship Cargo Control System

1. System Overview

The CARGOPRO system is mainly composed of four relatively independent subsystems, including: liquid level telemetry system, valve remote control system, independent high-level and high-high-level alarm system and large tank flooding alarm system. It can monitor and alarm the cargo control system of the whole ship and is an important part of the electrical system of the whole ship. The system has a large number of digital and analog measurement points, and these measurement points are of many types and widely distributed, so there are high requirements for the safety, reliability and communication capabilities of the system. We use GE Fanuc 90-30, VersaMax Micro and other series of PLC as the control unit of the system, VersaMax Remote I/O as the remote station for signal acquisition, Genius Bus, Mod Bus, Profibus and other general bus protocols as internal communication protocols, and communicate with the industrial control software iFix through the TCP/IP network protocol to realize human-computer dialogue.

2. System Solution

The system diagram of the entire CARGOPRO system is shown in Figure 1:


2.1 Liquid level telemetry system

The liquid level telemetry system adopts the design concept of decentralized collection and centralized control to detect and alarm the liquid level of the corresponding compartment, the temperature of the liquid cargo tank, and the draft of the four corners. Since the signals to be collected are widely distributed, the number and types are large, all signals are collected through the GE VersaMax Remote I/O modules installed in each collection box to ensure the accuracy of the collected signals. The GE VersaMax Remote I/O module communicates with the PLC master station installed in the cargo control console through GE's Genius Bus bus protocol and sends the collected signals to the PLC CPU module. After calculation, the CPU sends the control signal to the GE VersaMax Remote I/O module via the Genius Bus to achieve remote control.

The host computer includes an industrial computer, a switch, a printer and software. The industrial computer communicates with the PLC master station through the TCP/IP protocol to realize the information exchange between the monitoring software HMI/SCADA iFix and the PLC. The operator can realize real-time monitoring of all measurement points and process alarm information through the iFix software.

2.2 Independent high-level and high-high-level alarm systems

The system collects independent alarm signals to alarm high liquid level and high-high liquid level signals in cargo tanks, sewage tanks, ballast water tanks and other compartments. Using independent VersaMax Micro series PLC as the controller and QuickPanel View series touch screen as the HMI, a relatively independent control system is formed to realize the display and control of corresponding alarm signals. The
touch screen as the HMI communicates with the PLC controller through the Mod Bus bus protocol. The display of all alarm signals and the operator's operation of the system are fully realized on a touch screen, making the entire system extremely streamlined.

2.3 Large cabin water ingress alarm system

The system uses the principle of pressure level measurement to convert the pressure signal into a 4-20mA current signal and sends it to the VersaMax Micro series PLC control station on the cargo control table. The PLC control station communicates with the QuickPanel View series touch screen via TCP/IP to realize the display and control of alarm signals. The entire system can realize independent liquid level display, alarm display and control.

2.4 Valve remote control system

The valve remote control system consists of the cargo control console GE Fanuc 90-30 series PLC control master station, the solenoid valve box VersaMax Remote I/O PLC acquisition control station, the valve remote control dedicated industrial computer, the hydraulic power pump station, the solenoid valve box (including the emergency valve block), the hydraulic valve, the hand pump, and the emergency hand pump. The valve remote control device uses an electric-hydraulic drive device to control the action of the solenoid valve to achieve remote control of the opening and closing of the cargo oil and ballast tank pipeline valves. The valve opening and closing operation and valve position indication are all on the valve remote control dedicated display screen on the cargo control console.

The hydraulic remote control valve can be switched on and off at the PLC control master station of the cargo control station. The switch indication of the switch valve is red indicating that the valve is closed and green indicating that the valve is open; the opening valve has an opening indication and control. The solenoid valve box PLC control station is connected to the cargo control station PLC master station through Genius Bus. According to the operation requirements of the cargo control station PLC control station, the corresponding solenoid valve is controlled, and the oil circuit inlet and outlet direction is controlled through the instantaneous power-on reversing and locking function of the solenoid valve to achieve the purpose of switching the valve; the valve position indication and opening control signals of all remote control valves are sent to the solenoid valve box PLC control station, and sent to the cargo control station PLC control station through Genius Bus for reception.

The host computer includes an industrial computer, a switch, a printer and software. The industrial computer communicates with the PLC master station through the TCP/IP protocol to realize the information exchange between the monitoring software HMI/SCADA iFix and the PLC, and realize the control and status display of the valve and the alarm history record and query.

3. System Features

GE's PLC is used as the control and signal acquisition module to ensure the stability and safety of the system operation to the maximum extent; the design of decentralized acquisition and centralized control makes the acquisition and control of various signals accurate and convenient; it is compatible with a variety of general bus protocols, such as Genius Bus, Mod Bus, ProfiBus, etc., which greatly expands the scope of application of the system; the advanced modular packaging design makes each subsystem relatively independent and can run independently, while the subsystems can also be seamlessly connected and work in coordination to meet the special needs of customers and realize personalized combinations; a variety of human-machine interfaces, such as IPC, touch screen, MIMIC board, etc., ensure that operators can easily and quickly obtain information and realize control.

4. Conclusion

The CARGOPRO system has extremely high safety and stability, a friendly human-machine interface, and stable communications. It has been used on many ships and has passed ship inspections by many classification societies.