When there is coolant, oil mist, water mist, and dust in the working environment of the grating ruler, compressed air needs to be connected to the grating ruler housing to achieve an IP64 protection level, which can effectively prevent the grating ruler from being contaminated. Both ends of the grating ruler and the reading head are equipped with interfaces for connecting compressed air. The compressed air connected to the grating ruler must meet the requirements of DINISO8573-1. Generally, industrial compressed air cannot meet the requirements and cannot be directly connected to the grating ruler. It must pass through the two-stage filtration, drying, and pressure regulation of the AI series air filter before being connected to the grating ruler.