Reliance O-57411-2L Resolver Input Module

Reliance O-57411-2L Resolver Input Module is a legacy AutoMax PLC I/O card designed to bring resolver-position feedback into the controller backplane. Also cataloged as 57C411 with the documentation reference J-3640-1 Rev 10, this module accepts the two-output sine and cosine signals from a rotary resolver, demodulates them, and presents a digital position input to the AutoMax backplane. It was used in Reliance Electric AutoMax systems, the predecessor line eventually incorporated into Reliance/Rockwell product families. The 'O-57411-2L' designation identifies the same module across multiple parts and documentation, reflecting variation in packaging or revision history. Typical applications include servo motor feedback for precise positioning in automation tasks such as machine tools, packaging equipment, and material handling where resolver feedback is required. The module is designed to install in the Reliance Electric/AutoMax I/O backplane and interact with other AutoMax modules to synchronize motion control and logic operations. Because these are legacy components, availability is primarily through surplus and aftermarket listings; the module is frequently found under the 0-57411-2L or 57C411 identifiers, with Rev 10 documentation indicating the version level. As with other resolver input cards, it serves as the interface between resolver-based sensing hardware and the PLC, enabling the controller to interpret angular position data for closed-loop control workflows.