Intelligent module series products are our latest new generation of electrical measurement series products, using a new intelligent product design, abandoning the analog circuit design concept of traditional analog sensors, adopting digital and modular design schemes, and changing the traditional analog wiring design method with intelligent digital bus design. The intelligent module and sensor detection system make the configuration equipment assembly process more concise, the equipment digitalization and automation degree higher, and the equipment debugging more convenient.The digital small current sensor is a new type of digital output small current sensor, which can replace the current mainstream analog small current sensor in the market. The digital small current sensor adopts a new intelligent bus design method. It is connected in parallel to the 485 bus, and is connected to the host computer through the 485 bus interface, and all sampled data are transmitted to the host computer in the way of bus addressing. The insulation detection system thus constituted has the advantages of simple process, low production cost and high degree of automation.