Design of gas collection system for livestock houses based on PLC
1. College of Engineering, Huazhong Agricultural University, Wuhan 430070, China; 2. Key Laboratory of Agricultural Equipment in Mid-lower Yangtze River, Ministry of Agriculture and Rural Affairs, Wuhan 430070, China
Abstract：To satisfy the needs of continuous monitoring of harmful gas concentrations in livestock houses, a multichannel gas collection system for livestock houses is designed by PLC. The system is composed of PLC, group solenoid valve, sensor, vacuum pump and pipeline, which realizes the functions of automatic gas collection, manual collection and calibration collection. In order to reduce the lag time of the gas in the pipeline, the system adopts a synchronous working mode of the bypass circuit and the analysis circuit. The single-channel acquisition takes 50s. Using collection pipes with lengths of 1 m, 10 m, and 20 m, the detection error tests were performed on carbon dioxide and ammonia respectively. The detection errors of carbon dioxide were 0.42%, 0.78%, and 1.03%. The detection errors of ammonia gas were 1.19%, 3.67% and 7.11%. This shows that the gas detection error increases with the extension of the collection pipeline, and the maximum length of the collection pipeline is preferably not more than 20 m. The system’s device has compact structure, stable operation, and simple operation system. When combined with an adjustable absorption spectrum (TDLAS) gas detection device or gas analyzer, it can realize continuous monitoring of gas concentrations in multiple areas in livestock houses, and provide a scientific basis for analyzing the environmental factors of livestock houses and regulating the environment of livestock house.
李鑫安 1,谭鹤群 1,2，艾正茂 1. 基于可编程控制器的畜禽舍气体采集系统设计[J]. 河北农业大学学报, 2020, 43(5): 114-121.
LI Xinan1, TAN Hequn1,2, AI Zhengmao1. Design of gas collection system for livestock houses based on PLC. Journal of Hebei Agricultural University , 2020, 43(5): 114-121.
2020, Vol. 43 
