Abstract: The SSI signal interface is the most common signal output mode for absolute angle encoders, yet generally there is no SSI interface for the industrial controller and microcontroller. In this paper, a universal data acquisition instrument that could read position signals of the SSI encoder through simulating the SSI encoder communication protocol via IO signal is designed. The data acquisition instrument not only realizes numerical display of the output signal angle, but also realizes communication with the upper computer and transmits the position data to the upper computer. The data acquisition instrument has been applied and verified on two-dimensional automatic turntable of the special equipment for a certain type of product; the result shows that the position data is accurate, the work is stable and reliable, and it has good application value.