Development of fire extinguishing device control box detector

1 System composition and working principle Figure 1 is the hardware principle block diagram of the control box detector. The entire system consists of a control box, a drive and signal adapter board, an analog signal part, an industrial computer, a display, an I/O timing board PCI1751 , a signal acquisition card PCL813 , a special keyboard, etc.
　　

　　The control box is the product to be tested. The control box, drive conversion board, and control box detector are connected to each other through adapter cables. The power supply of the control box and the circuit board is provided by the control box detector. The working voltage and working current of the tested control box are connected to the signal acquisition card through a mutual inductor. When measuring, the user can first select the test item through a dedicated keyboard and preset the initial state of the detector and the fire extinguisher bottle. After the setting is completed, the control box detector provides the light source signal required for the test through the I/O card to simulate the fire signal detected by the detector. The control box detector monitors the emergency switch signal, the fan start signal, and the spray bottle signal output by the control box during the measurement process, and simulates the fire extinguisher bottle state and feeds back the corresponding signal to the control box. At the end of the measurement, the corresponding bottle state and the measurement data of each parameter are displayed on the LCD display, and the qualified parameters are determined according to the qualified criteria, and finally the corresponding data report is printed.

2 Boards The PCI1751 board is a PCI bus-based board with 48 -bit I/O ports and timer / counter. It provides 48- bit parallel digital input / output ports and three 16- bit timers. It has the same working mode as 8255 mode 0 , but its buffer circuit provides stronger driving capability than 8255. The board simulates two 8255 chips to provide 48 digital I/O ports. The six 8 -bit I/O ports are divided into two groups: A0 , B0 , C0 and A1 , B1 , C1 . Each I/O port can be configured as an input / output port through software . The timing function of the board is realized by an 8254 compatible chip. The timers in the three timers / counters can be configured into five working modes. The timers can be used independently through jumper switches, or they can be cascaded to form 32- bit or 48- bit timers. The timing pulse of the timer comes from a 10 MHz active crystal oscillator on the board . The 　　PCL813 board is an isolated 32- channel data acquisition board with 12 -bit resolution based on the ISA bus . The AD sampling method is successive approximation, bipolar and unipolar signal input, 10 V and 20 V working ranges, built-in software programmable gain, and the maximum sampling rate is 25 kHz .
　　

3 Software compilation C++Builder 5 is used as the tool for software compilation . The measurement is mainly completed by directly controlling the I/O timing board PCL1751 and the data acquisition card AD813 through the host. Therefore, the self-defined function can be used to replace the board's own driver. Under Window 98 , the port operation can be realized through BCB5 embedded assembly. The specific code is as follows: With the above 4 functions, the board address can be set. The PCI1751 board is a board based on the PCI bus . The PCI bus will automatically allocate board resources according to the board resource requirements. Therefore, the board can be directly plugged into the industrial computer. Since the board needs to be directly controlled, there is no need to install the driver. In "My Computer", you can see that the base address of the PCI1751 board automatically assigned by the system is 0xC000 , and then cancel the automatic address assignment option to ensure that the address remains unchanged. Since PCL813 is a card based on ISA bus , the card address must be set manually by jumper. First, find the unused IO address, and then set the card address according to the card resource requirements and the manual. The card base address in the system is 0x230 . In this way, BCB5 can be used in Windows 98 environment to operate the port in combination with custom input and output functions. [page] 　　The following is part of the code:
　　
　　
　　
　　
　　

　　
　　
　　

4 Conclusion This system uses C++ Builder development software and Windows 98 development platform, which reduces the difficulty of system development and makes the system have good scalability. The detector has the characteristics of friendly human-machine interface, convenient operation, high intelligence, good real-time performance, and accurate measurement. The control box detector is used for debugging, testing, and acceptance of control box finished products and single boards. Using this detector, not only can the unpotted circuit single board of the control box be debugged and tested through the transfer cable and process shell, but also after the circuit board is potted or assembled into a finished product, multiple parameters of the control box can still be tested, which improves the production efficiency and quality of the product. Practice has proved the feasibility of the system solution. The system meets the various technical indicators of the test technology requirements and has passed the acceptance.
　　

references

[ 1 ] Liu Leshan , Ouyang Xingming, Liu Xueqing. Microcomputer Interface Technology and Application [ M ]. Wuhan : Huazhong University of Science and Technology Press, 2000. [ 2 ] Zhang Guoxiong, Jin Zhuanzhi. Measurement and Control Circuit [ M ]. Beijing: Machinery Industry Press, 2001. [ 3 ] Zheng Li, Dong Yuan. C++ Language Programming [ M ]. 2nd Edition. Beijing: Tsinghua University Press , 2001. [ 4 ] Chen Zhouzao, Chen Canhuang. A Thorough Study of C++Builder4


[ M ]. Beijing : China Railway Publishing House, 2000