Severe demands on measuring circuits for the multi-rollers method are needed compared with single-roller method in the measurement of large wheel diameter. In view of the correction for engraving error of grating and the need for the correlated data analysis, a novel multi-modal sampling technology for measuring grating signals based on double counters was put forward, the design of multi-modal sampling circuits was described in detail and the simulation results of distinguishing and rejecting skidding signals of large wheel were given, which indicated that by the multi-modal sampling technology with double counters, the weak skidding signals on very small areas of large wheel surface could be distinguished and the sampling data were reliable.