The system is widely used in applications requiring hot water supply, such as office buildings, hotel baths, etc., especially suitable for areas with abundant solar energy resources. The control system uses Delta DVP40ES2 PLC, DVP04PT-E2, DVP04AD-E2, and Delta Human Machine Interface HMI B07S515. The system has stable working performance and high degree of automation. Especially the design of constant temperature water discharge saves a lot of water resources. The design of the heat collecting cycle makes the solar hot water efficiently circulate into the water tank. The auxiliary heat source is added to solve the problem of insufficient solar energy resources. Hot water supply under.
2 system compositionDelta series human-machine interface, Delta ES2 series CPU, Delta PT-E2 series temperature control module, Delta AD-E2 series analog to digital module, solar collector, electric heating wire (or air source heat pump, etc. Auxiliary heat source), insulated water tank, bath control pump, heat collecting circulation pump, solenoid valve, temperature sensor, liquid level sensor, power transmitter, etc., as shown in Figure 1.
(1) Automatic water supply
The liquid level sensor p is installed in the water tank. When the water in the water tank is lower than a certain value (20%), the automatic water supply valve is powered on, the water tank automatically replenishes water, when the water level reaches the set value (90%), the automatic water supply valve is powered off, and the automatic water supply stops. .
(2) Collecting heat cycle
When the collector water temperature (outlet installation temperature sensor) is higher than the water temperature in the water tank and reaches the PLC set start temperature difference (6-10 degrees Celsius), the heat collecting circulation pump starts; the low temperature water in the collecting water tank enters In the vacuum tube collector group, the relatively high temperature water in the collector is circulated to the hot water tank, so that the water temperature in the water tank rises. When the temperature difference decreases to the system set stop temperature difference (1-3 degrees Celsius), the circulation pump stops and the heat collection cycle stops. Repeatedly, the heat is gradually transferred to the water tank, and the temperature of the water in the water tank is gradually increased until the temperature required for the bath is reached.
(3) Pipeline constant temperature water
The constant temperature return water pipeline is mainly for the indoor bathing hot water pipeline. In order to ensure that there is hot water in the nozzle when the bath is opened, and the waste of invalid cold water is reduced, the hot water return pipeline must be installed to take the pipeline circulation measure. . The pipeline circulation adopts the constant temperature circulation mode. The temperature detection sensor and the circulation pump are installed at appropriate positions in the indoor hot water return pipeline, and a temperature range is set to control the operation of the pump. When the water temperature in the pipeline is lower than the set value, the bathing pipe circulation pump is started, and the low-temperature hot water in the pipeline is driven into the insulated water tank. When the water temperature reaches the set value, the pipeline circulation pump stops running.
(4) Constant temperature control
When the water temperature in the water tank is lower than a certain value, the collector cannot reach the temperature of the hot water of the bath. At this time, the electric heating or other auxiliary heat source (air source heat pump) in the water tank is turned on to ensure that any weather conditions can be guaranteed. The hot water supply is essential.
(5) Winter antifreeze cycle
The outdoor pipe (between the insulated water tank and the collector) may be frozen in the cold winter, so it is necessary to have an antifreeze cycle function; when the collector temperature (detection sensor temperature measurement) is lower than a certain value (2-5 degrees Celsius), Start the collector heat pump and pump the hot water in the heat preservation tank into the collector to prevent the pipeline from freezing.
4 electrical control system designThe system host computer selects the HMI b7s515 model touch screen to realize the visual monitoring and control of the system operation. The lower computer selects the Delta series PLC, the host CPU selects DVP40ES2, the temperature module selects 04PT-E2, and the AD module selects 04AD-E2. The expansion module can also be added to the power transmitter to monitor the power of the solenoid, circulation pump and auxiliary heat source, as shown in Figure 2.
(1) The temperature-related signal measured by the temperature sensor is converted into digital quantity by the PT module and then transmitted back to the CPU of the PLC. The status of the PLC is reflected on the touch screen to realize real-time monitoring of the data, as shown in Fig. 3.
Figure 3 External wiring diagram of temperature sensor PT100 and DVP04PT module
(2) After the electric level signal of the water tank is measured, the electric signal is converted into a standard current signal of 4-20 mA by the liquid level transmitter, and then converted into a digital signal by the AD module and transmitted back to the PLC. The PLC is based on the set value. Make a judgment to control the opening and closing of the water tank solenoid valve, as shown in Figure 4.
Figure 4 External wiring diagram of liquid level transmitter and 04AD-E2 module
In addition, the temperature measured by each temperature sensor directly represents the temperature of each component to control the operation of the system. Therefore, the installation position of the temperature sensor is extremely important. The water temperature at the temperature sensor installation must be representative of the average temperature of the portion being measured.
5 electrical control system software development(1) WPL Soft develops PLC control program
WPL Soft is the program programming software used by Delta Electronic Programmable Controller DVP series in Windows existing system environment. Delta PLC uses program memory to perform logic operation, sequence operation, timing and counting. And operations such as arithmetic operations, and can control various types of mechanical or production processes through digital or analog inputs and outputs.
The key to system control is the comparison of temperature and liquid level, which can be easily realized through the comparison instruction of PLC.
The frequency and accuracy of reading parameters of each expansion module are the key of this control system. The temperature control module and AD conversion module provided by Delta PLC can easily realize the automatic and precise control of the system.
(2) Touch screen human machine interface (HMI) program
The touch screen replaces the mouse and keyboard functions. The input device installed at the front end of the display is the medium for transmitting and exchanging information between the human and the control system, and the dialogue interface, including long-distance information transmission and control, which is an important part of the control system. . The switch quantity is added to the PLC control program and associated with the HMI register to realize the association between the HMI and the PLC, as shown in Figure 5.
Figure 5 PLC program controls the start and stop of the heat cycle pump
6 ConclusionThis application realizes the automatic control and monitoring of the hot water system through Delta PLC and its touch screen. The addition of auxiliary heat source solves the shortcoming of single solar energy affected by weather conditions. (If the auxiliary heat source uses air source heat pump, the system compares Electric heating has the advantages of low power consumption, safety, comfort, environmental protection and low carbon.
On the control system, multiple parameters such as temperature, liquid level and power are added, which are reflected on the touch screen to realize visual monitoring of important parameters of the operating system. The user has a clear grasp of the water temperature in the water tank, the temperature of the bath hot water, the water volume in the water tank, and the system power consumption. The actual system is stable in operation, convenient in maintenance and maintenance, and can be highly popularized, especially suitable for hot water supply in hotel baths, office buildings and other occasions. In addition, according to the requirements of indoor heating in winter, the hot water of suitable temperature can be automatically controlled to enter the heating pipe to realize the hot water control system compatible with bathing and heating, as shown in the attached table.
Introduction
SCOTECH manufactures a full range of furnace transformers including arc furnace transformer(EAF), ladle furnace transformer, induction furnace transformer, electroslag furnace transformer, blast furnace transformer, calcium carbide furnace transformer, and other more kinds of furnace transformer. With the advanced design and thorough quality management system, we had become one of the most reliable furnace transformer manufacturers in China. we do not compromise on the quality, we ensure that each one of our delivered units has passed the most strictly testing and that makes us confidently to provide the longest quality warranty to our customers. We export our furnace transformers to all major global markets.
Application
Electric arc furnace (EAF) transformers are normally used in steel plant for smelting the scrap iron and for refining steel, also required for many different furnace processes and applications, such as smelting glasses and ceramics, manufacturing or refining many other materials, such as ferrochromium, ferromanganese, different abrasive materials (oxides and nitrides), semiconducting base materials.
Duty
Steel arc furnace transformers operate under very severe conditions with regard to frequent over-currents and over-voltages generated by short-circuits in the furnace and the operation of the high voltage (HV) circuit breaker (furnace breaker). The continuous at high utilization. loading is cyclic, while in other applications the loading is more
Scope of supply
SCOTECH`s furnace transformers Including arc furnace transformer, ladle furnace transformer, induction furnace transformer, electroslag furnace transformer, blast furnace transformer, calcium carbide furnace transformer, and other more kinds of furnace transformer
Voltage level: up to 220KV
Rating level: up to 100MVA
Why SCOTECH
Long history- Focus on transformer manufacturing since 1934.
Technical support – 134 engineers stand by for you 24/7.
Manufacturing-advanced production and testing equipment, strict QA system.
Perfect service-The complete customer service package (from quotation to energization)
Furnace Transformer,Arc Furnace Transformer,Induction Furnace Transformer,Submerged Arc Furnace Transformer
Jiangshan Scotech Electrical Co.,Ltd , https://www.scotech.com