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20/05/2024

Temperature controller. Replacing and adjusting the temperature controller on a cargo crane

Greetings! In this article we will change the temperature controller of a cargo crane. It has failed and for this reason the crane hydraulic protection system based on oil temperature does not work.

Temperature controller. Replacing and adjusting the temperature controller on a cargo crane

The temperature controller (PID controller) on the crane, together with the PT100 RTD (Resistance Temperature Detector) sensor, are key elements in protecting the crane hydraulics from oil overheating. 

The sensor is located in the expansion tank through which the hydraulic system oil constantly circulates. When the temperature in the tank changes, the thermal resistance of the sensor changes, and the current and voltage in the sensor circuit changes accordingly.

Circuit diagram of operation of the temperature sensor on the cargo crane
Circuit diagram of operation of the temperature sensor on the cargo crane

The temperature controller (PID controller) at a temperature in the tank of 80°C and above issues an alarm for high oil temperature and stops the hydraulic system. At a temperature of 55°C and below, the controller stops the cooling fan of the oil cooler; at a temperature of 60°C and above, the cooling fans will operate in automatic mode (on the diagram, the inscription “off 60°C” may be misleading).

High Temperature Instructions
High Temperature Instructions
Troubleshooting manual
Troubleshooting manual

If any problems arise with the controller, sensor or PLC, then you should contact the troubleshooting manual offered by the manufacturer.

In our case, the problem is with the temperature controller, the display of which has failed and requires replacement.

Replacing the controller
Replacing the controller
Disconnecting wires
Disconnecting wires

We replace the controller with a new one, and it is very important to mark all the contact wires in advance, and also copy the numbering into your notebook. The controller control circuit must be de-energized in advance. You can use the connection diagram as you wish.

Controller Settings
Controller Settings
Controller operating mode settings
Controller operating mode settings
Controller PID component settings
Controller PID component settings
Controller Parameter Settings
Controller Parameter Settings

After replacing the controller, it needs to be configured. We check the settings on all cargo cranes and, using the instructions from the manufacturer, set up the PID controller.

Controller controls
Controller controls

In our case, it is important to select the option "Deviation alarm" - "High & Low alarm" and set the setpoint to 40°C. This setup can be confusing because... we should have 80°C.

40°C value on lower display (12°C low temperature alarm)
40°C value on lower display (12°C low temperature alarm)
Change the value of the high temperature ALH (from the factory it was set to 839)
Change the value of the high temperature ALH (from the factory it was set to 839)

But everything is explained by the fact that the controller operates in deviation mode. We set High alarm to 40°C, Low alarm to 20°C and the temperature setpoint on the lower display to 40°C. Thus, at a temperature of 40 + 40 there will be an alarm for a high temperature of 80°C, and at a temperature of 40 - 20 = 20°C - for a low temperature. The low temperature alarm here is informational.

Disassembling the old controllerDisassembling the old controller
Disassembling the old controller

So we installed a new temperature controller on a cargo crane, configured it and tested it in operation. In this article I wanted to focus on the fact that it is not enough to simply change controllers and set operating settings; you need to check all the settings inside the PID controller and see in what mode it operates.

Crane model: DMC DDKC-3026-00 (Dongnam Marine Crane)

Temperature controller model: Digital temperature controller DX3 (Hanyoungnux)

Also read other articles about DMC cargo cranes:

  1. Problems with cargo cranes. Some problems with cargo cranes that occur on the ship
  2. The cargo crane does not slew. Troubleshooting
  3. The crane hook goes up slowly. The cargo crane is not working. Troubleshooting
  4. PLC failure. The cargo crane does not start. Troubleshooting
  5. Motor Fault on the crane. Troubleshooting
  6. The crane jib is luffing down under its own weight. Troubleshooting

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