Programmable manipulators (PLCs) have always played an important role in industrial field control. With the increase of national investment in the water supply industry, the level of automation of water plant operation has been continuously improved, and the application of PLC in the water supply industry has gradually increased. The touch screen and PLC are used together, so that the use of PLC is more sensitive, and together with the ability to set parameters, display data, and depict the automation process with animation, the application of PLC can be visualized.
Variable frequency and constant pressure water supply has become a mainstream in the water supply industry, and it is an important means to ensure that the water supply network is in a constant pressure state. The perfect network communication function of modern inverter provides necessary support for the synchronous operation of the motor, long-distance centralized control and online monitoring. Through the touch screen connected to the PLC, the control can be more visual and intuitive, and the operation is more simple and convenient.
The combination of PLC, touch screen and inverter, the communication method is used to control the inverter to complete the variable frequency constant pressure water supply.
The variable frequency constant pressure water supply system is mainly composed of PLC, frequency converter, touch screen, pressure transmitter, power and control circuit and pump unit. Users can understand and control the operation of the system through the touch screen, and can also understand and control the operation of the system through the indicator lights and buttons on the control cabinet panel, and the transfer switch. Through the pressure transmitter installed on the outlet pipe network, the outlet pressure signal is turned into a standard signal of 4-20mA or 0-10V and sent to the built-in PID conditioner of the PLC, and the operating frequency is output to the inverter after PID calculation and comparison with the given pressure parameters. The control system is controlled by the inverter to control the speed of the pump to regulate the water supply, according to the different water consumption, the PLC frequency outputs the operation frequency of the given inverter, and then adjusts the speed of the pump to reach the constant pressure water supply. The internal program set by the PLC drives the output of the I/O port switch to complete the switching of the AC contactor group, so as to harmoniously put the number of pump motors into operation, and complete the switch of the motor start and stop, frequency conversion and power frequency. After adjusting the number of motors put into work and controlling the frequency conversion speed of one motor in the motor unit, the working pressure of the system pipe network is always stable, and then the intention of constant pressure water supply is reached.
The system has two operating methods: manual and active. In the manual method, the pump is controlled by the touch screen or the start and stop buttons on the control cabinet, and the start and stop of the 1#-3# pump can be controlled according to the demand, and the method is mainly used for equipment debugging, active fault and maintenance. When it is actively running, the 1# water pump is first operated by frequency conversion, and the output frequency of the inverter rises from 0HZ, and the PID conditioner compares the received signal with the given pressure and sends it to the inverter for control. If the pressure does not work, the frequency rises to 50HZ, and the output of the I/O port switch is driven by the program set by the PLC to complete the switching of the AC contactor group, so that the 1# pump frequency conversion is quickly switched to the power frequency, and the 2# pump is started by frequency conversion, if the pressure still does not reach the set pressure, the 2# pump is switched from frequency conversion to power frequency, and the 3# pump is started by frequency conversion; If the water consumption is reduced, the PLC control starts to cut the pump from the first, and together with the PID conditioning parameters, the system runs smoothly and maintains the pressure of the pipe network at all times.
If there is an instantaneous power failure, the system will be shut down, and after the power supply is restored to normal, it will be manually started, and the system will actively restore to the initial state and start operation. The active function of frequency conversion is the most basic function of the system, and the system actively completes the operation, such as starting, stopping and circulating frequency conversion of multiple pumps.
Before communication, it is necessary to set the communication parameters of the PLC, touch screen and inverter correctly. This system is defined as the Modbus protocol, the baud rate is 9600, the data bit is 8, there is no check, and the abort bit is 1. In addition to setting the communication parameters, the inverter also needs to enable "free parking" to protect the motor.
The system uses Mitsubishi FX-200 PLC, relay output, PLC programming selection of Mitsubishi PLC special programming software, the software provides a complete programming environment, offline programming, online connection and debugging. In order to improve the cost performance of the whole system, the system selects the switching input and output of the programmable controller to control the start and stop of the motor, active input, regular switching, frequency conversion of the water supply pump and fault alarm, etc., and the PID built in the PLC gives the speed, set pressure, frequency, current, voltage and other simulated signals.
In the past, when the water pressure was high, the inverter pump was usually stopped, and then the inverter was switched to the pump running at the power frequency for conditioning. This switching method is theoretically more advanced than the direct switching method of power frequency, but it simply causes frequent start and stop of the pump set, and then reduces the service life of the equipment. In this system, the operation method of direct shutdown frequency pump is selected, which is quickly adjusted by the inverter, and only the appropriate parameter setting is required to complete the shock-free switching of the pump group, so that the water pressure transition is smooth, and the large-scale fluctuation of water pressure and the short-term water shortage when the water pressure is too low are effectively avoided, and the water supply quality is improved.
|
More on that
|
Touchscreen click accuracy decreases - Hitech
Fault phenomenon: A touch screen, its click accuracy decreases, and the cursor is difficult to locate.
Fault analysis and processing
1) Run the touch screen calibration program. (Start - Settings - Control Panel - Acoustic Screen ---Capberate Button).
...
|
|
Hitec touch screen tutorial
The touch screen interface is the same as the general interface, in addition to the touch screen interface, other user interfaces include web interface, software interface, game interface and mobile phone interface. Touchscreen interfaces have a lot of similarities with them: the most basic thing is that they are all interactive systems, and they are all ...
|
|
Key points of use of industrial touch screen all-in-one machine
Storage humidity between 10%-90% Temperature -20°C-60°C If the ambient conditions exceed or approach the critical value, condensation will occur inside the display. The power transformer and other coils inside are also prone to leakage when wet, and may even cause a short circuit in the wiring. If you find that the obvious ...
|
|
Human-machine interface technology - Hitec touch screen
NaturalID: NaturalID skills can meet the explosive increase in demand for biometric sensing, from mobile payment transactions and cloud services to enterprise mobile device security, including the entire ecosystem under FIDO (Online Fast Identity Authentication).
...
|
|
What is the difference between inline and outboard installation of the touch screen?
Embedded device is a common installation method, which can make two objects fit together to form a whole, which looks simple, beautiful and does not take up space, which is the popular installation method at present.
In the industrial field, the device methods of industrial displays are rich and diverse, including snap-on, ...
|
|
Precautions for man-machine interface touch screen all-in-one machine - Hitech
1. The touch screen part is a glass product, the glass corners are relatively sharp, and the assembly needs to be carried out with gloves/finger covers.
2. The touch screen part is a fragile glass product, and do not exert a strong impact on the touch screen during assembly.
3. Pick and place products ...
|
|
The difference between human-machine interface and touch screen
In life, we often come into contact with touch screens, and many people will regard the human-machine interface as a touch screen, in a strict sense, there is a fundamental difference between the two.
"Touch screen" is only in the human machine interface product ...
|
|
Analysis of the advantages and disadvantages of Hitec capacitive touch screen
The light transmittance and clarity of the capacitive contact screen are better than those of the four-wire resistive screen, and of course, it cannot be compared with the external acoustic wave screen and the five-wire resistive screen**.
The reflection of the capacitive screen is severe, and the transmittance of the four-layer composite contact screen of the capacitive skill to each wavelength of light is uneven, and there is a problem of color distortion, ...
|
|
Touchscreen usage skills - Hitec
1. Run your app in full screen
Remove the file name bar and menu bar so you can enjoy the benefits of running the entire screen.
2. Choose bright colors (don't use black)
The bright color of the set can hide the finger prints, reduce the dazzling light and star...
|
|
Hitec touch screen response failure analysis
First, the touch screen response time is very long
Problem phenomenon: A contact screen, touch the monitor screen with your fingers, and it takes a long time to react.
Problem profiling and processing
This could be a touch screen with moving water droplets, just wipe it with a dry, soft cloth ...
|
|
Key points for the use of industrial control touch screen all-in-one machine - Hitec
Storage humidity between 10%-90% Temperature -20°C-60°C If the ambient conditions exceed or approach the critical value, condensation will occur inside the display. The power transformer and other coils inside are also prone to leakage when wet, and may even cause a short circuit in the wiring. If you find that the obvious ...
|
|
Resistance touch screen non-response detection method - Hitech
1) Check whether the connection of the touch screen is right, and whether the connection of a cable connected to the keyboard port of the host (take the working voltage of the 5 volt touch screen from the keyboard port) is connected, please check the connection.
2) Observe the situation of the touch screen controlling the box light, if ...
|
|
The internal composition of the touch screen - Hitec
The interior of the touch screen can be roughly divided into: communication interface unit, driver unit, memory variable unit, and display unit. In addition to the display unit, the other 3 units are invisible to us inside the touch screen.
1. Communication interface ...
|
|
The defect of the capacitive touch screen - Hitec
The light transmittance and clarity of the capacitive contact screen are better than those of the four-wire resistive screen, and of course it cannot be compared with the external acoustic wave screen and the five-wire resistive screen.
The capacitive screen is severely reflective, and the four-layer composite contact screen of the capacitive skill has a strong impact on each wavelength ...
|
|
The Hitec touch screen software sets up the application method to run automatically
1. First of all, we work on the SoftPanel program (this program generally does not create shortcuts on the desktop, users can click the [Start Menu] in the lower right corner of the desktop to find the SoftPanel in the list of applications called out).
...
|
|
The difference between human-machine interface and touch screen ——— Hitech
Human Machine Interaction (HMI), also known as user interface or user interface, is a preface and dialogue interface for transmitting and communicating information between humans and computers, and is an important part of the computer system. It is the interaction and information gap between the system and the user.
|
|
Categories and Advantages and Disadvantages of Resistive Touch - Hitech
Resistance contact is divided into four-wire resistance and five-wire resistance contact, the simple difference is four wires and five wires in the functional area.
A constant voltage of 5V is added to each layer of the two-layer transparent metal layer with four-wire resistance analogue technology: ...
|
|
Industrial touch panel PC function - Hitech
Tablet PC is a relatively simple, natural, and practical new type of human-computer interaction technology machine and equipment, which is mainly used for some self-ribbed business processes. There are many types, among which the industrial contact tablet PC, which brings together computer technology, network technology, sound planning, ...
|
|
HMI Faults and Solutions for Human-Machine Interfaces - Hitec
Human Machine Interaction (HMI), also known as user interface or user interface, is a preface and dialogue interface for transmitting and communicating information between humans and computers, and is an important part of computer systems. It is the interaction and information between the system and the user ...
|
|
Precautions for the use of industrial touch film screens - Hitec
1. The resolution needs to be fixed
Every time the screen resolution of the industrial touch film screen is adjusted, there will be some shifts, and the solution is to manually adjust or restart the machine, but this frequent adjustment is not good for the machine.
...
|
|
Contact
working hours
