In addition to providing DC 5V, the UN200 main unit's internal power supply also provides DC 24V. The DC 24V power supply, also known as the sensor power supply, can be used by the CPU module and expansion modules to detect the status of DC signal input points. If the user uses sensors, it can also be used as the sensor's power supply. Generally, the DC 24V power supply used by the input and output points of the CPU module and expansion modules is provided externally by the user.
1. Load capacity of the PLC's internal DC 5V power supply
The UN200 PLC provides internal DC 5V power to the CPU module and expansion modules. The expansion modules receive their 5V power from the CPU module via a bus connector. The current supplied by the CPU module to its bus expansion interface is limited. Therefore, when configuring expansion modules, the load capacity of the DC 5V power supply provided by the CPU module must be carefully considered. Overloading the power supply can lead to unpredictable malfunctions or accidents. To ensure the power supply is not overloaded, the total DC 5V current consumed by all expansion modules should not exceed the current supplied by the CPU module. Otherwise, the system must be reconfigured. After system configuration, the load capacity of the internal DC 5V power supply of the UN200 main unit must also be verified.
2. Load capacity of the PLC's internal DC 24V power supply
In addition to providing DC 5V, the UN200 main unit's internal power supply unit also provides DC 24V. This power supply can be used by the CPU module and expansion modules to detect the status of DC signal input points. It can also be used as a power supply for sensors used in the system. Generally, the DC 24V power supply used by the input and output points of the CPU module and expansion modules is provided externally by the user. If the internal DC 24V power supply of the CPU module must be used, its load capacity must be verified to ensure that the total current consumed by the CPU module and all expansion modules does not exceed the maximum current (400mA) provided by the internal DC 24V power supply.
When using this system, if the user needs to provide an external DC24V power supply, the connection method should be noted: the sensor power supply of the host and the external DC24V power supply provided by the user cannot be connected in parallel. Otherwise, it will cause the two power supplies to compete and affect their respective outputs, causing one or both power supplies to fail at the same time, and causing the PLC system to produce incorrect operations, thereby causing system failure.
