PLC Power supply

The power supply converts the AC line voltage to DC voltage and sends the power to the programmable controller system with the help of an electronic circuit. This power supply is similar to the power supply of a computer. This power supply sends a certain amount of voltage and current to the supply system through rectifiers, filters and regulated voltages and current. The power supply converts 230VAC line voltage to direct current voltage, such as + 5V or + 15V and + 24VAC. The PLC is connected to the processor, memory and input / output modules by a single housing or other unit to the system for power supply.

Power supply is used in PLC according to high temperature and humidity. This power supply is designed to remove AC power or electrical noise from a single line. The power supply can be divided into an external power supply and an internal power supply. In internal power supply, power is measured in all internal operations of the PLC on a fixed voltage and current basis. Internal power supply systems operate the internal parts of the PLC, which include chips, transistor diodes, etc.

AC and DC external power supplies are supplied to the input / output modules. The power supply system is shown in Fig. In this system power supply is provided to the PLC through transformer, rectifier circuit, filter network and voltage regulator. EC power supply is mainly used in power supply.

Power supply system

Transformer - The nominal phase voltage present in the transformer is 230V RMS. And frequency is 50 Hz. To rectify the AC supply The transformer is passed through, which consists of two regions. First the transformer steps the AC voltage up or step down, then it isolates the rectifier circuit through the power line thereby reducing the electric shock. The step down transformer is used to convert the AC line voltage to the fixed magnitude of the power supply. The secondary widening center of the transformer is taped. The transformer is a center tape circuit that has a high step down ratio between primary and secondary widening. Each AC input power supply generates a shutdown signal on the backplane while the AC line voltage drops to the lower voltage limit. This removes the shutdown signal when the line voltage returns to the lower voltage limit. Shutdown is necessary so that certain data can be stored in the memory. If the transformer is too small then the sine wave on its chip will be high. When the voltage is below the lower voltage limit, it senses the power supply and shuts down the module from the chassis.
Rectifier - A rectifier is an electronic device that converts alternating current into direct current. The rectifier converts AC power to DC power with the -ve half cycle subtracted by alternating voltage. It connects to the load in the + ve half cycle and disconnects from the load in the -ve half cycle
Filter Network - The full wave bridge rectifier consists of an output pulse that holds the DC and AC components. This type of pulse output is used for battery charging and driving the DC motor. If the DC voltage is to be received, then the filter circuit is placed between the rectifier output and the R load. The filter circuit removes various types of impurities from the filter component. The diagram of the filter circuit is shown in the figure.
Filter circuit
The filter circuit removes the AC component from the rectifier output and transmits only the DC component to the load. In this way, the constant DC voltage load is obtained
Voltage Regulator - The voltage regulator is an electronic device that maintains the voltage even when load variation and input AC voltage changes. The voltage regulation device is used in the ordnary power supply, which maintains the value of the DC voltage constant. The circuit diagram of the voltage regulator is shown in the figure. It has AC supply of 230V. A capacitor circuit is added between its bridge rectifier and IC voltage regulator. Its output voltage employs a registive load that maintains the output voltage.
Voltage Regulator circuit