Schneider Electric AM-R911-000 Hot-Standby Processor Module

The AM-R911-000 Hot Standby Processor Module from Schneider Electric provides fault-tolerant redundancy for Modicon 984-series chassis-mount PLCs. It is designed for use in a system with two identically configured 984 controllers (984A, 984B, or 984X) and installs in an option slot to form a hot-standby pair that mirrors I/O state and RAM while the primary processes the ladder logic. In operation, the standby remains synchronized with the primary and will assume control within 13 to 48 milliseconds if the primary fails, with the requirement that all hardware and firmware in the primary and standby controllers be identical. The AM-R911-000 works with S908 Remote I/O Processor modules, and Schneider Electric distinguishes hot-standby options by host configuration: AM-R911-000 (and AM-S911-000) are for chassis-mount 984 controllers, while AS-S911-800 is the slot-mount alternative.