The Design Of Control System For Large-flow Fire Cannon Based On Bus Network

With the constantly expanded building scale, fire disasters become more and morediversified, which makes the rescue work much more difficult. In the chemical industry andother high-risk occasions, some fire cannons with large flow and long range are needed to jetwater simultaneously so as to put out fire effectively and decrease loss of people’s lives andproperty. Due to the shortcomings such as small flow, finite range of existing fire cannons,designed the control system for large-flow fire cannon based on bus network, developednetwork and communicate with the monitoring host computer in control room via CAN busand ZigBee wireless network, to control the fire cannons distributed in every area to jet waterto fire source and finally put out fire. The control system was composed of main controlmodule, drive, detection and protection module, ZigBee wireless network and CAN busnetwork module, and power supply module. This paper researched the following contents:(1) Because of large flow water jetting of the fire cannon, great driven torque is requiredto rotate the fire cannon so as to aim at fire source, so adopted high-power DC motor asmotive power source for horizontal rotation and vertical pitching motion of fire cannon.Designed the main control module of the system by using the32-bit architecturemicrocontroller chip STM32F103VET6based on the Cortex-M3kernel, and developed thecommonly used peripheral equipment interface circuit such as USART serial interface circuit,TFT display interface circuit and USB bus communication interface circuit, etc.(2) Designed the driving module of fire cannon by using PWM timer of main controllerSTM32and intelligent motor driving chip BTN7970B to drive high-power DC motors inhorizontal and vertical direction of fire cannon, and developed two directions’ rotation limitposition detection circuit by using Holzer switch JK8002D. Designed detecting and protectingmodule using current detection function of the chip BTN7970B to detect real-timely workcurrent of motor. Studied the start-stop control and protection methods about work exceptionsof DC motor such as overload, the rotation control process of fire cannon and software design,etc. Completed the physical debugging of drive, positive and negative rotation control, andcurrent real-time detection of the high-power DC motors of large-flow fire cannon.(3) Researched the network architecture, network topology, the work process of theZigBee protocol stack and software design of ZigBee wireless communication technology,designed the ZigBee wireless network module of each fire cannon node using wireless radiofrequency transceiver CC2430, and set up a ZigBee star network topology structure withmonitoring host computer, realized wireless network communication with monitoring hostcomputer(network coordinator FFD) of each fire cannon node (terminal equipment RFD). (4) Researched the work principle, working process and software design of the CAN2.0B controller bxCAN of main controller STM32, designed the CAN bus network module ofeach fire cannon node using high speed CAN bus transceiver CTM1050, realized the CANbus master-slave communication with monitoring host computer of each fire cannon node.(5) Adopted DC24V switch power supply as input power supply of control system offire cannon, realized system power supply and electric isolate between the system maincontrol module, ZigBee wireless network and CAN bus module and drive, detection andprotection module using the switch power chip MC34063and with isolated output DC/DCpower module ZY2405WRBD-2W, enhanced the reliability of control system of fire cannon.