Major fire accidents have occurred, causing great losses to the lives and property of the country and the people. Therefore, the automatic fire protection system has received extensive attention from the party, the state and all walks of life, and has put forward higher and higher requirements for automatic fire alarm and automatic fire extinguishing system. At the same time, it has also greatly promoted the scientific research and development of the system. .
Here is a solution to the fire alarm and automatic fire extinguishing system. The system diagram is as follows:
The above picture shows the fire alarm and automatic fire extinguishing system provided by Shiqiang: This scheme is an alarm that uses the flue gas sensor and temperature sensor to cooperate with the microelectronic judgment circuit to drive the alarm or electromagnetic relay to achieve the fire warning or warning function. . Among them, Shiqiang's SI7055 temperature sensor plays an auxiliary role. The sensor transmits the collected information to Renesas MCU R5F117BCGFP , and then the processing unit transmits the MCUEFM32WG230F256 to the relay through the SI4438 wireless transceiver chip of SiliconLabs. The relay MCU is The information is transmitted to the PC of the main control part through the CAN bus, and the main control part realizes the water spray processing through the relay control motor, and the main control part can also issue an alarm display function. This requires radio waves to be good at wall penetration, while the wireless link budget is as high as possible, and the receiving sensitivity is better than -110dBm. Wireless smoke alarms need to use wireless chips to transmit electromagnetic waves carrying smoke alarm information. Several common wireless frequency bands below 1 GHz, such as 315, 433, 868, and 915 MHz, are suitable.
In this system, several chips of Shiqiang agent are used. Their application characteristics and advantages are as follows. You can also find the most up-to-date information on the Shiqiang component e-commerce APP:
Shiqiang agent Renesas MCU R5F117BCGFP:
The R5F117BCGFP integrates a wealth of analog functions including op amps, comparators, analog-to-digital converters and more. The product integrates up to four operational amplifiers. In high-speed operation mode, its stable operation waiting time is only 13us, which fully meets the requirements of general analog signal processing. The external fit with simple resistors and capacitors can be completed. The signal amplification, filtering and other processing saves the system design area.
In addition, R5F117BCGFP also integrates an analog-to-digital converter with a resolution of up to 17 channels and 12 bits. It uses a wide voltage supply and its supply voltage ranges from 1.6V to 3.6V. By reducing the supply voltage, the power consumption of the chip can be effectively reduced. The R5F117BCGFP chip has four operating modes, namely Operating mode, Halt mode, Stop mode, and Snooze mode. When R5F117BCGFP is in Operating mode and its operating frequency is 1MHz, its power consumption does not exceed 150uA, which can meet the power consumption and speed requirements of most industrial control applications. When the operating frequency is further reduced to 15KHz, its operating power consumption can be Reduced to 6uA. When the chip enters the Halt mode at this operating frequency, its power consumption does not exceed 2uA. In summary, R5F117BCGFP's superior power performance allows developers to be more comfortable in industrial control applications.
R5F117BCGFP is rich in resources on the chip. The code storage space is up to 32KB, the data storage space is up to 2KB, and the on-chip RAM is up to 3KB and 42 IO ports. The R5F117BCGFP operating temperature range is -40°C to +105°C. The chip integrates an on-chip voltage monitor to monitor the operating voltage of the system in real time, providing up to 12 levels of quantitative indicators. When the system is powered abnormally, it can report to the user in time to prevent accidents. This function is especially important for battery applications. Tell the user in advance that the battery is low.
SiliconLabsMCUEFM32WG230F256:
SiliconLabs' EFM32WG230F256 from Shiqiang agent is a high-performance 32-bit processor based on Cortex-M4 core with speed up to 48MHz. The DSP architecture supports floating-point unit operations. The FLASH memory space of the program is 256/128/64KB. Optional, RAM space is 32KB, IO port can be up to 56, DMA has 12 channels; its Peripheral Reflection System (PRS) has 12 channels, also has 128-bit and 256-bit hardware AES encryption, and 24 and The 32-bit RTC can be switched to an external backup battery in the event of a power loss. The EFM32WG230F256's memory protection unit has multiple power management modes: up to 20nA in 3V shutdown mode and 0.4μA in 3V supply with RTC shutdown; 3V shutdown In mode, the RAM and CPU can maintain a power consumption of 0.65μA; in 3V deep sleep mode, the power consumption is 0.95μA.
Wireless transceiver chip Si44xx:
In the fire alarm and automatic fire extinguishing system, there are two versions of the chip for customers to choose. Si4463 and Si4438, in which Si4438 operates in the range of 425MHz to 525MHz, while the Si4463 band is relatively wide, covering 315MHz, 868MHZ, and 915MHz. When the Si4463 operates at 169MHz and has a low rate of 500bps, its receiving sensitivity is typically -129dBm, and the transmit power can be 20dBm, which brings a very high link budget to customers. Its sleep power consumption is very low, the shutdown current is only 30nA, and the standby current is only 40nA. Together with the Epson high-performance 30MHz crystal from Shiqiang, the Ricoh power chip R1172 and the RF switch UPG2214, together with the corresponding matching network, form a complete wireless module.
Temperature sensor SI7055:
SiliconLabs has a wide range of temperature and humidity sensors featuring high reliability, miniaturization, high integration and unparalleled ease of use for a wide range of applications. Digital Temperature Sensors The Si705X Series features innovative signal processing and mixed-signal design techniques with high accuracy and industry-leading low power. Among them, including the cost-effective temperature sensor SI7055, its temperature acquisition accuracy can maintain ±0.5oC (max) over the entire operating temperature and voltage range, the operating voltage range is 1.9 to 3.6V, the operating temperature range is -40 to +125 between. The SI7055 has the advantage of low power consumption. The average power consumption is only 195nA at 1HZ sampling frequency, and the acquisition accuracy can reach 14-bit resolution. All the indicators of this product are industrially calibrated before leaving the factory, and are available in 3x3mm DFN package. Greatly reduce the space of PCB layout, and passed the AEC-Q100 automotive-level certification.
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