Description
Foxboro FBM239RH927AG
Technical Specifications
- Product Type: Redundant Discrete I/O Assembly.
- Base Module: FBM239 (16 Digital Inputs / 16 Digital Outputs).
- Redundancy Hardware: RH927AG Adapter.
- Signal Compatibility: Supports 30 Vdc, 60 Vdc, 120 Vac/125 Vdc, and 240 Vac inputs and outputs.
- Communication: Dual redundant 2 Mbps Module Fieldbus.
Functional Features
- Seamless Failover: Provides bumpless transfer to the secondary module upon primary failure, with zero disruption to field devices.
- Continuous Synchronization: Both modules process I/O states in parallel, with the controller validating data integrity.
- Hot-Swap Capability: Allows for the replacement of a failed module without shutting down the process or disturbing field wiring.
- High-Density I/O: Offers 16 fully redundant digital inputs and 16 fully redundant digital outputs in a compact footprint.
Application Scenarios
Mandatory for safety-critical discrete control, such as emergency shutdown (ESD) systems, fire and gas detection, critical motor starters, and high-value process interlocks where a single point of failure is unacceptable.
Performance Parameters
- Failover Time: Bumpless, typically <100ms, transparent to the control logic.
- Data Consistency: Bit-exact synchronization between primary and secondary modules.
- Input Response: Millisecond-level scanning for fast sequence control.
- Output Drive: Capable of driving external solid-state relays or directly switching loads (with appropriate TA).
Material Composition
Combines the industrial-grade FBM239 with the RH927AG redundancy adapter, which features high-reliability relays and isolation circuits. Housed in a rugged, extruded aluminum enclosure that provides excellent EMI shielding and physical protection.
Structural Characteristics
Occupies two adjacent module positions on the baseplate (FBM + Redundancy Adapter). Features comprehensive front-panel LED indicators for module status, redundancy health, and individual I/O channel states.
Working Principle
Both modules independently read field inputs and drive field outputs. The redundant control software compares the data from both modules and uses a voting algorithm to determine the valid state. If the primary module fails, the secondary immediately assumes control, and the field devices remain energized or de-energized without interruption.
Installation Requirements
Install the FBM239 and RH927AG in adjacent slots as specified by the baseplate documentation. Connect the redundancy sync cable if required. Use appropriate Terminal Assemblies (TAs) or Termination Assembly Adapters (TAAs) for field wiring.
Usage Precautions
- Never remove both modules simultaneously.
- Monitor redundancy status in system diagnostics; address sync loss immediately.
- Test failover during scheduled maintenance to verify redundancy integrity.
- Ensure field wiring is secure to prevent intermittent contact issues that could confuse the voting logic.
