With the rapid development of China's economy, people's quality of life is constantly improving, and the demand for energy is increasing. However, current conventional energy sources are becoming increasingly scarce and prices continue to rise. As a non-polluting and renewable energy source, solar energy has received more and more attention, and its solar energy collection project is more and more widely recognized by people for its unique energy-saving and environmental protection advantages. Nanda Automation Technology Co., Ltd. adopts NA200 series PLC to scientifically and rationally develop a set of special solar heat collection control system for a solar energy equipment manufacturer, which has achieved good application results.。

System Configuration

The following products are selected for this solar collector project:

CPU module: one CPU201-2402

Analog input: AIM201-0401

Text display: OP0401

Additional water level detection components, heat collectors, water tanks, brackets, pipes and other auxiliary parts are added.

Process introduction

(1) Manual water addition/heating/circulation

When the water level of the water tank is too low, the temperature of the water tank is too low, and the temperature difference is too large, manual adjustment can be made manually, and the automatic process is terminated during the adjustment process.

(2) Automatic constant water level adding water/heating

The water level of the water tank is automatically added when the water level is lower than the constant water level, and stops when the water level is higher than the constant water level. The temperature of the water tank is automatically heated below the set temperature, and the heating is stopped when the temperature exceeds a certain range of the set temperature.

(3) A temperature difference cycle is adopted between the collector and the water tank

Under the premise of satisfying the water level of the water tank, the temperature difference between the collector temperature and the temperature in the water tank is set on the text screen. If the temperature difference exceeds the upper limit of the temperature difference, the cycle is started. As the temperature on both sides approaches the lower limit of the temperature difference, the circulation is closed, and the circulation pump is automatically opened and closed.

(4) Timed water addition/timed heating/timed circulation of the water tank in the time period

In the set time period, when the water level of the water tank drops to the lower limit of the water level, the water is automatically added and the water level of the water tank rises. When the time is up, stop adding water. When the water level of the water tank exceeds half, if the temperature of the water tank is too low within the set period of time, the heating is automatically started and the temperature starts to rise; when the time is up, the heating is stopped.

Within the set time period, the temperature difference between the collector and the water tank is automatically adjusted by the circulation pump.

(5) Self-inspection of water failure/self-inspection of heating failure/self-inspection of circulation failure

When the continuous water addition/heating/circulation time is too long, but there is no significant change in the water level, temperature and temperature difference of the water tank, the water addition process/heating process/circulation process will be automatically stopped.

The technological process of this system is mainly composed of the above aspects. The NA200 series PLC has its own real-time clock (RTC) function. The programming software NA200Pro can read the year, month, day, hour, minute, second, and week, so that the timing time set on the text screen can communicate with the PLC on time and run the entire process in real time and with high efficiency.

The solar energy collection engineering control system with NA200 PLC and text screen as the core has simple operation, convenient operation and low failure rate, creating a healthy and comfortable living space for users. The solar energy project will usher in a brilliant tomorrow.