ABB Australia have released a winch control programme that can be used in different control system configurations found within the marine environment. The winch control programme is suitable for winch applications. It incorporates built-in programmable logic controller (PLC) features, enabling the drive to be used without any external PLC.
The winch application can be programmed within the PLC that communicates with the ABB Australia’s industrial drive through fieldbus gateways. The ABB Australia’s industrial drive is certified for marine use and when combined with the winch control programme, it can serve as an alternative to traditional hydraulic winch controllers used in anchoring and mooring. This eliminates high maintenance costs and performance inefficiencies, while improving operator safety and overall system reliability.
A key benefit of the ABB Australia’s industrial drive is its motor control platform and Direct Torque Control (DTC). DTC enables the drive to achieve full torque at zero speed without the need for a feedback encoder. Using a feedback encoder can be a problem on board a vessel as the harsh climate on deck can damage the encoder or interfere with the feedback signal to the motors.
Using the ABB Australia’s industrial drive’s digital I/Os along with the winch control programme enables the direct operation of the winch from three control stands located on the port, starboard and upper deck of a vessel. This lets the operator to control the speed of the winch while in a harbour, for example, from anywhere on the vessel, irrespective of whether the vessel is coming alongside on port or starboard.
The Winch control programme enables a control stand to be operated with the other two stands disabled or with all three stands active at the same time. From each stand, operators can start and stop or by way of a joystick raise or lower the winch. A set of protection functions is built into the winch control programme to safeguard the health and safety of everyone working in the location of the winch.
From each control stand, an anchor mode can be selected which lets the winch raise or lower an anchor. As this procedure requires careful speed control, the operators manually control the joystick at their chosen stand.
Among the in-built protection functions are slip detection which detects any high load on the chain, if it becomes snagged when raising the anchor. High load creates a speed difference between the winch drum and the motor shaft and activates a load switch. The speed/torque of the winch motor is immediately reduced to a level set by the winch manufacturer. This prevents damage to the motor shaft, winch drum or clutch between the drum and motor.
Another protection feature is anchor-in protection. As the anchor raises and reaches the end of its limit, the winch control programme detects the anchor winch speed and motor torque level, together with the relative length of the chain. It then slows down the winch automatically, allowing operators to manually complete the task and controlling the joystick to the zero position.
When mooring a vessel to a harbour or pier, the tension within the mooring ropes can be controlled manually from any of the three control stands using the winch control programme, while staying in full view of the rope movement. Without the winch control programme, there is a risk that the force within the rope becomes too high, resulting in the rope breaking. As this is a speed control application, the winch control programme detects the high force in the rope through changes in the torque and controls the speed accordingly.
Peak torque protection prevents breakage in the rope. It detects severe tightening of the rope and immediately sends a signal to adjust the speed, saving the rope and protecting the winch system from overload. The speed and torque is reduced to a level that the operators can control before the mechanical brake is applied and locked or change over to auto mooring mode.
The winch control programme features an integrated brake control logic, which uses torque memory and pre-magnetising to open and close the mechanical brake safely. Additional safety is achieved using brake feedback status from the brake hardware to the drive’s I/O board to monitor brake status compared to drive run/stop status.
The drive also features adaptive programming. The adaptive/function block programming technique is included as standard and allows winch features to be changed or modified on-site without waiting for further software upgrades from the manufacturer. Adaptive programming is suitable for over speed monitoring and speed match.