Schneider S911 Hot Standby Module

Redundant Control for Critical Operations

The Schneider S911 provides automatic system redundancy for Modicon Quantum PLCs. This module enables seamless switchover between primary and backup controllers. It ensures continuous operation without process interruption.

Technical Specifications

Redundancy Architecture and Switchover Logic

The S911 continuously monitors the primary controller’s health status. It tracks program execution, power supply condition, and communication integrity. The module instantly detects any primary controller failure or fault. Upon detection, the Schneider S911 initiates an automatic switchover to the backup controller. This transfer takes only 20 milliseconds from fault detection. The process continues without any interruption to field I/O devices.

Data Synchronization and Fiber Optic Link

Two fiber optic ports connect the primary and backup S911 modules directly. A duplex fiber cable transmits data in both directions simultaneously. The modules synchronize all program data, registers, and I/O states in real time. Every scan cycle updates the backup controller with current process values. The Schneider S911 supports fiber optic distances up to 500 meters. This distance allows you to locate backup controllers in separate cabinets or rooms.

System Compatibility and Integration

The S911 works exclusively with Quantum 140CPU65xx and 140CPU66xx series processors. It requires two identical processors for primary and backup operation. The module connects to the rack backplane through the standard Quantum interface. An RS-232 port provides configuration and diagnostic access. The Schneider S911 tracks the status of up to 4096 I/O points per controller. Five status LEDs show active, standby, sync, and fault conditions clearly.

Physical Dimensions and Installation Guidelines

The Schneider S911 weighs 0.320 kilograms for secure rack mounting. Its height measures 123.9mm, width 40.1mm, and depth 144.1mm. Install one S911 module in the primary controller rack. Install a second S911 in the backup controller rack. The module consumes 3.8 watts from the backplane power supply. It operates reliably from 0°C to +60°C ambient temperature. Keep fiber optic cables away from high-voltage power lines.

Energy Storage and Battery Maintenance

The S911 uses a 1200 mAh lithium battery for configuration retention. This battery stores redundancy parameters and network settings during power loss. The battery lasts approximately five years under normal operation. Replace the battery every four years for preventive maintenance. The red FLT LED flashes when the battery voltage drops too low. Always replace the battery with the Schneider S911 module powered on.