The host of the direct digital control system generally uses the Windows operating system, and then configures the corresponding application software. Although Windows is not a real-time operating system, IPC's computational speed is fast enough to offset the non-real-time effects of the Windows operating system. The application software includes monitoring configuration software and real-time database to ensure that the system has a very friendly man-machine interface, easy to establish I/O data points, control loop configuration, operation screen drawing, print report generation, and alarm information release. .
2. Process input and output device
The process input and output devices include AI, DI, AO, and DO boards. The AI and DI boards convert signals from the process parameters and status of the instrument to digital signals and send them to the host. The AI and DO boards output the host. The digital control signals are converted to signals that are adapted to the various actuators. It is divided into two categories, one is the I/O board integrated with the host, and the other is the independent I/O data acquisition unit, which communicates with the host through the serial bus. The signal type of the AI board is 4~20mA DC, 1~5V DC, millivolt, thermal resistance and thermocouple. The input mode is single-ended or differential. The signal types of the DI board are switches, buttons and other contacts. The signal type of the AO board is 4~20mADC, 1~5V DC, etc. The signal types of the DO card are relay contacts, active switching elements, and the like.
3. Incoming interface device
Human interface devices allow operators to monitor and operate the production process, including CRT or LCD, keyboard and mouse, alarm and display devices, printers, and more.
4. External equipment