In May 1992, Southwest Pharmaceutical Co., Ltd. was established. Most of the raw materials of medicinal materials are chemical raw materials, and harmful gases such as hydrogen sulfide, aldehydes and ammonia will be produced in the treatment process, which have pungent odor and are harmful to health. Acetone, methanol, alcohol and other reagents used in the pharmaceutical process pose the threat of fire and explosion. The project uses the ASD5300C, ASD5300 detector and JB-TB-ASD5100 controller.