Methods and systems for controlling the synchronization of diagnostic cycles and data conversion for redundant I/O applications are provided. An exemplary system comprises a first analog input module adapted to request mastership with respect to a second analog input module, output a synchronization pulse to said second analog input module, initiate a diagnostic cycle of said second analog input module, and initiate a data conversion cycle, and wherein said second analog input module, said second analog input module are adapted to assume a slave role with respect to said first analog input module. Numerous other aspects are provided.