Application of PLC Technology in Intelligent Street Lighting System

1. Features of PLC Technology

(1) High reliability and strong anti-interference

PLC input and output interface circuits usually use optocouplers to transmit signals. This photoelectric isolation measure avoids the electrical connection between the external circuit and the internal circuit, and can effectively suppress the influence of external interference power on the PLC. At the same time, the external high voltage can be prevented from being connected in series, thereby reducing the failure. In addition, many filter circuits are set in the PLC power supply circuit and input/output circuit to suppress high-frequency interference signals. At the same time, methods such as shielding, voltage stabilization, and protection are adopted for the internal power supply of the PLC to reduce external interference.

PLC host structure material has high strength, good sealing and strong shock resistance. All electronic components have undergone strict inspection, and certain measures will be taken between each module to reduce radiation. Its self-monitoring function can alert in time when a failure occurs, avoiding larger failures. The internal processing process does not rely on mechanical electric shock, but adopts the method of cyclic scanning, which can increase the anti-interference ability.

(2) Three-electrical integration can be realized

PLC combines the electrical control (logic control), electrical instrument (process control) and electrical junction (motion control). It can be easily and flexibly combined into various control systems of different scales and requirements to meet the needs of various industrial controls.

(3) easy to use

It is more convenient to use PLC to realize the control of the system. The reasons are as follows: First, the establishment of PLC control logic is to replace hardware wiring with programs. Secondly, the hardware of PLC is highly integrated and has been integrated into various small modules. Moreover, these modules are matched and have been serialized and standardized. The modules required for various control systems are mostly available from PLC manufacturers and can be purchased in the market. Therefore, the hardware system configuration and construction are also very convenient. Because of this, the use of programmable logic controllers is widely used. For software, its program can be edited, and it is not difficult to edit. In terms of hardware, its configuration is variable and easy to change.

2. Application of PLC Technology in Intelligent Street Light Control System

(1) Working principle

The PLC technology is used to control the street lights. The main design is to turn on all the street lights through the control center when there are many pedestrians and vehicles on the road and the light is dim. When there are few pedestrians and vehicles on the road, adjust the lighting of the street lights according to the time. In the early morning, the lighting ratio is the smallest, about 40%. The lighting conditions of each street light can be monitored by the control center at each time period, and the faulty street light can also be monitored in time and repaired in time.

(2) Street light brightness detection circuit

The brightness detection circuit can detect the lighting conditions of the road lights at any time, so that the street lights are automatically turned off during the day and turned on automatically at night.

The detection of street light temperature and current can realize A/D conversion through ADC0809. An ADC0809 can manage the temperature and current of four street lights, and can control the A/D converter at different time periods.

(3) Temperature and current detection

After the A/D converter is turned off, the temperature of the street light will drop and the current will decrease rapidly. However, the detection circuit is still not closed at this time, so there will be a misjudgment. In view of this, the registration can be realized through the data selector. By changing the value of D1, the current that selects the data device shows a high level state, so that the ADC0809 can work normally.

In this way, the current and temperature of any street light can be checked. The ADC0809 can realize the inspection of eight states to maintain the continuity of the smart street light system.

PLC technology can remotely control the street light system and detect faults in real time. It can monitor a specific line, arrange maintenance personnel to repair or replace it in time, provide convenience for people’s travel, and promote the orderly operation of urban traffic.

After years of use, PLC technology has been accepted by many enterprises, and its penetration is very extensive.

With the continuous improvement of urban infrastructure, the urban street light control system is also gradually developing. PLC technology is applied to the urban intelligent street lighting system. PLC technology has the characteristics of strong reliability, strong anti-interference, low energy consumption and easy installation. The introduction of PLC technology into smart street lights can effectively improve the problems of insufficient traditional control and limited control capacity. The system runs stably, can realize real-time online detection and management of energy, and can meet the needs of remote online remote street light running status screen detection in the future. In addition, it can fully realize its functions in urban construction and promote the improvement of urban economic benefits.