Design of residential common street lamp power distributor Wang Weidao (Department of Electronic Information, Hunan Building Materials College, Hengyang, Hunan 421008), briefly described the problems of residential public streetlights, and proposed the use of electricity distributors to illuminate the time average of street lamps. The method of apportioning electricity charges introduces the working principle, hardware circuit and software design of the power distributor... All the street lamps in the corridor are connected in parallel, and the household meter is connected through the distributor. The street lamp zero line is shared, and the street lamp phase line is controlled by the switches S1, S2, and S12 in the distributor, and is respectively connected to the indoor phase lines of the household 1, 2, and 12 meters. The street light switch meter uses the self-recovery button and is connected to the distributor in parallel. As long as any street light button is pressed, the distributor will control the switches S1, S2, ..., S12 in turn to realize the power consumption of all the street lamps. equally distributed.
3 power distributor hardware circuit design 3.1 power distributor main controller based on the cost factor, functional factors and performance factors (reliability, safety, low power consumption) of the power distributor, select the microcontroller AT89C52 as the power distribution The control core of the device. AT89C52 is Wang Ren: Design of a residential common street lamp power distributor. A low-power, high-performance CMOS 8-bit MCU with full instruction system and pins compatible with 80C52. It has 8Kbytes of flash memory and 256 bytes of RAM. Functional modules such as two I/O lines, three 16-bit timer/counters, and six interrupt sources (using two-level management), especially its standby mode can meet the system's low power requirements.
3.2 The clock of the power distributor, the reset circuit and the clock of the keyboard AT89C52 are generated by the external crystal oscillator and the on-chip circuit. The crystal frequency is 12MHz. The watchdog and reset circuit are realized by IMP813L. The IMP813L itself has a power-on reset, manual reset function, power supply voltage monitoring, and a 1.6s watchdog timer. The watchdog circuit is used to ensure that the system can automatically recover from a dead state to a normal working state. The dog feed signal is sent from P2.4. As long as the dog can be fed in time, the system reset can be avoided.
The buttons KA and IKB are mainly used to set the time when the street lamp is lit. KA increases and KB decreases. IKA and KB are connected to P2.7 pins. The KA and IKB button signals are sent to the P3. Part 1 interrupt request signal (falling edge trigger), and the AT89C52 is woken up. The button discrimination and lighting time settings are all completed in the interrupt service routine of the external interrupt 1.
3.3 Ambient illumination detection circuit The detection circuit is implemented by a single power comparator LM393. R4 is a photoresistor. When the ambient illuminance becomes low, so that the resistance of R4 is greater than the resistance of R3, LM393 flips, and the output of the low-level signal of pin 1 is sent to P2. 5. The AT89C52 is based on the level of this pin. Decide whether you can use street lights (P2.5 is low to light the street lights) to achieve energy saving.
3.4 Street Lights The S1, S2, and S12 in the button circuit are street light buttons distributed at the door of each floor. When any of them is pressed, a falling edge is generated on the P3.2(/INT0) pin by the optocoupler TLP52-2, triggering the external interrupt 0, waking up the AT 89C52. Interrupt service at the external interrupt 0 In the program, whether or not to allow the lighting to be judged, if permitted, controls the relay to operate and illuminate the street light.
3.5 Relay Interface Circuit The interface circuit is isolated by optical isolation device TLP52-4 to improve the anti-interference ability of the system and achieve isolation of strong and weak current systems. The relay action signal of the middle resident 1 is output from P1. 0, and the 2 and 15 pins of 52-4 are controlled to control the conduction and deactivation of the triode å©1, thereby controlling the action of the relay J1.
4 power distributor software design system software mainly includes the main program, external interrupt 0, 1, timer 0, interrupt service program and other parts.
4.1 Main program The main program is used to complete the system initialization, feed the watchdog and set the system to enter the standby energy-saving working mode and other tasks. The main program flow diagram is as shown.
When the system is initialized, the priority level of two external interrupts 0 and 1 should be set to low, the falling edge trigger mode should be used and its interrupt should be opened; and the two timers 0 and 1 are set to allow interrupts, and the interrupt priority level is set to high. ; Timer 0, the working mode (both mode 1) should be set, the initial value should be counted, and the timer should be turned off.
After the system is initialized, all street lights should be turned off in time, and the watchdog should be fed to set the system to enter the energy-saving standby state (set the lowest bit ID of PCON to 1). When the system wakes up due to interference, it should be forced to soft reset by the branch instruction, initialized again and enter IDL; if it is normal wake-up, it will enter the external interrupt 0 or 1 interrupt service routine < 4.2 interrupt service routine external interrupt 0 interrupt service program processing First, first close the external interrupt 0, and whether the lighting button is falsely triggered and whether the lighting is allowed to be judged. If it is false trigger or the ambient illumination is not allowed to be lit, then after the open external interrupt 0, the interrupt is immediately returned, the main program is executed, and the entry is made. Standby mode.
Otherwise, feed the dog and extinguish all street lights. In order to ensure the reliable operation of the relay, after all the street lights are turned off, the timer 0 must be started for delay, and the delay time is 15ms. In this process, the dog should be fed continuously to avoid interference. When the delay time is up, the timer 0 is turned off; then the user 1 lights up the street light command, and the timer 1 is started at the same time, and the control lighting time is 10s. During the 10s timing process, the dog must be fed continuously, the timing time is up, and the timing is turned off. 1, send relay J1 open command, and start timer 0 again, delay 15ms, ensure that relay J1 is disconnected, then send user 2 to illuminate the street light command, in this order to light; finally, after user 12 lights up, Open the outer interrupt 0 and interrupt the return.
During the execution of the INT0 interrupt service routine, the street light is on for about 10.3 s, and the average share time of each household is 10. 3s. The INT0 interrupt service routine flow diagram is as shown.
In the process of the external interrupt 1 interrupt service program, first, the external interrupt 1 is turned off, and the determination of whether the button is erroneously triggered is also performed. If it is true, the initial value of the timer 1 should be adjusted according to the button to adjust the lighting time of each household. Finally, the open external interrupt 1 interrupts the execution of the main program.
In the timer 0, interrupt service routine processing, mainly used to reload the initial value. Since the lighting time is long, the timer 1 timer can be set to 100 ms. In the external interrupt 0 interrupt service routine, the special counting unit is set to discriminate the number of interruptions of the timer 1, and 100 times indicates that the 10s lighting time is up. The 15ms relay delay processing is relatively simple and will not be discussed here.
The power distributor is in a standby state for most of the time, and can only be woken up by the button when using the street lamp or adjusting the lighting time, and enters the normal working state. In addition, due to the role of the watchdog, it can automatically return to normal when the system crashes. Therefore, it not only has high stability, reliability and safety, but also has the characteristics of low cost, is easy to be accepted by residents, and has certain marketing and application value.
1 Shen Hongwei. Design examples and analysis of single-chip application system. Beijing: Beijing University of Aeronautics and Astronautics Press, 2003 2 Yang Zhenjiang, et al. New devices and applications in intelligent instrumentation and data acquisition systems.
Xi'an: Xi'an University of Electronic Science and Technology Press, 2001. (Continued from page 47) Class B degrees of freedom are VB = %. Synthetic standard uncertainty is the effective degree of freedom Veff =. Confidence probability, effective degree of freedom check t distribution table , the coverage factor is available. When the confidence probability is p=95%, the coverage factor is kp=2.58. The measurement uncertainty of any given amplitude is verified by selecting any point. For example, when AM= 45%, the calibration estimate can be obtained by the Taguchi method. The value is 45.7%, the measurement uncertainty is 0.4%, and the calibration data estimation interval at this point is . The calibration data obtained by HP8902A is 45.8%, and the calibration estimate is consistent with the measured value.
6 Conclusion The Taguchi method has been widely used in evaluating the measurement methods and the advantages and disadvantages of measurement equipment. In this paper, the Taguchi method is used to infer the calibration formula and measurement uncertainty of the instrument, and the practical application is verified to be correct and reasonable. In this way, not only the calibration formula can be inferred, the calibration estimate of any point is obtained, and the measurement uncertainty is given, and the calibration cost can be greatly saved and the calibration time can be shortened. The calculation process of the Taguchi method is suitable for computer programming, making the popularization and application of this method possible.
1 Han Jun. Measurement quality engineering. Beijing: China Metrology Publishing House, 2000 2 Tiankou Xuanyi. Measurement Management Design Manual. Translated by German. Shanghai: Shanghai Translation Publishing Company, 1989 3 Ye Depei compiled. Measurement uncertainty. The Standards and Metrology Bureau of the National Defense Science and Technology Commission, 4 Li Shenan compiled. Estimation and expression of uncertainty in measurement results. Beijing: China Metrology Press, 1997 JJF105-1999. Evaluation and Evaluation of Measurement Uncertainty Welcome to the advertisement of bookmark2 GJB37599. Representation and Evaluation of Measurement Uncertainty
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