The instrument application in plastic industry is very extensive, and parameters such as temperature, pressure, level and flow need to be measured and controlled. Plastic molding peripheral auxiliary equipment, including mold temperature control system, industrial chiller, dehumidification drying system, crushing and recycling device, automatic metering and mixing device, etc. are inseparable from instrument measurement and control. For example, the water temperature machine and the oil temperature machine of the mold temperature control system can realize the precise and safe control of the water level with the pressure switch and float liquid level switch to ensure safe production without dry burning. Rotary paddle level switch, tuning fork level switch can be used to raw material, recycling and other hoppers of plastic auxiliary machines. Pneumatic vibrator can be used in the process of blanking and conveying to remove accumulation and provide auxiliary material transportation.