Design of Cherry Greenhouse Temperature Control System Based on CAN Bus

The application of CAN bus in the greenhouse temperature control in cherry is introduced. The design of STM32 based controller, two wire Pt100 temperature acquisition thermistor bridge measurement circuit through the output differential signal, amplifying the information by differential amplifier LM324, through the CAN bus transmission of analog signal, digital temperature the information through the STM32 comes with the A/D module. According to the actual temperature in the Greenhouse Cherry control requirements to control the ventilation device operation, finally realize the effective control of temperature in the Greenhouse Cherry. Introduction Cherry in greenhouse planting to control the temperature higher, the temperature sensor and the ventilation device in the temperature control process in plastic greenhouse needs more arrangement, CAN bus control circuit so the less connected to control the temperature in the greenhouse cherry. Controller Area Network (CAN) has the advantages of high communication speed and long communication distance, especially the ability to connect multiple unit nodes[1]. It improves the efficiency of the control system and reduces the management cost. In recent years, CAN bus control mode have been more and more widely used. Therefore, this paper introduces a temperature control system of Greenhouse Cherry STM32 and based on CAN bus, through the host computer to control the lower machine to achieve the monitoring of the temperature, and the temperature control target to control the ventilation device, then realize the temperature in the Greenhouse Cherry dynamic balance, provide a suitable temperature for cherry the growth of. Overall Design of Temperature Control System The main block diagram of the temperature control system is shown in Fig 1. It is mainly composed of the host computer, the RS232 serial module, the STM32 master controller, the CAN transceiver, the control node and so on. The main function of the control node is to collect the temperature signals from the Pt100 temperature sensor and upload it to the host computer, and finally control the operation of the ventilation device according to the needs of temperature control, and achieve the control objectives. The hardware of the temperature control system adopts the STM32 controller with CAN function, the control mode of CAN transceiver, the control mode has less control port, the hardware circuit connection is simple, and the software program is convenient to call. In the temperature control of cherry in greenhouse, shed every point will have a ventilation ventilation device and a corresponding temperature sensor. The main control objective control system is to detect the ventilation shed point temperature, real-time display on the display, and according to the temperature control requirements, control the ventilation device to maintain a stable temperature action. The STM32 master controller selects the microprocessor of the 32 bit STM32F103 enhancement type ARM core produced by stmicroelectronics. The STM processor itself features a CAN controller that can be directly connected to the CAN transceiver[2]. In addition, the processor also has 2 road 12 bit A/D conversion modules, each A/D module has 16 external channels, fully This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/). Copyright © 2017, the Authors. Published by Atlantis Press. 7th International Conference on Education, Management, Information and Computer Science (ICEMC 2017) Advances in Computer Science Research (ACSR), volume 73