What is hmi?Explaining the basics of hmi program
Recently many friends are concerned about hmi program related topics, so what is this hmi in the end? Why do so many people like to study this program? Let faceui give you a detailed explanation of the relevant issues, want to know more about this knowledge, come in and learn it.
What is HMI?
In fact, HMI is broadly interpreted as “an interface between users and machines to communicate, communicate and receive information”. For example, in a factory, we need to collect information about the temperature, humidity, and the status of the machines in each area of the factory, and monitor and record these parameters through a master controller, and deal with them when some unexpected situations occur. This is a typical SCADA/HMI application. In general, HMI systems must have several basic capabilities: Real-time data trending – displaying the captured data on the screen immediately. Automatic data logging – automatically stores data in a database for later viewing. Historical data trending – visualize the data in the database. Report generation and printing – the information can be converted into report format and can be printed out. Graphic interface control – the operator can directly control the machine and other devices through the graphic interface. Alarm generation and logging – The user can define some alarm generation conditions, such as excessive temperature or pressure exceeding the threshold value, in which case the system will generate an alarm and notify the operator to deal with it.
How to write the hmi program controller?
Here the controller is must have a serial port, and the level of the serial port should match the touch screen.
The controller program consists of two parts.
Sending commands. Controller through the serial port to the touch screen to send instructions for the touch screen display. For example, if the touch screen is currently on page 1, the controller sends a string command to the touch screen: t0.txt=”controller board instrumentation software development find me”, then you can let the text control t0 on page 1 display the text “controller board instrumentation software development find me”. For other specific commands, check the product manual.
Receive data from the touch screen. The controller should monitor the serial port to receive data from the touch screen at any time, which includes information about the control’s events, such as key presses, page switches, and so on. For the data format, you still need to refer to the product manual.
The GUI is ready and the controller program is written, so I thought it was perfect, but the reality is often a slap in the face. Either there is a problem here or there, then you need to debug.
Serial Assistant is a good software to display the data sent and received serial port, serial download line is also needed. Install the serial assistant on the computer and connect the serial download cable. When the other end of the serial download cable is connected to the touch screen, the serial assistant simulates the controller. You can see the information sent and received on the serial assistant, and envision a visual comparison, and the problem is generally nothing to hide.
The above is only an introduction to a serial touch screen development method, different screens have different methods, according to the manufacturer’s manual to develop, for example, there is another touch screen development is basically all controlled by the controller’s instructions, the development software is only used to generate the background of the touch screen, the computer will be the picture and Chinese characters dot matrix through the development software pre-stored in the memory of the serial screen, and then the controller through the serial port Then the controller sends commands through the serial port to call the display.