Description
Foxboro FBM22 PM900HS
Technical Specifications
- Module Model: FBM22 (PM900HS)
- Channel Configuration: 1 Analog Input (AI) / 1 Analog Output (AO)
- System Compatibility: Foxboro I/A Series Controllers
- Bus Interface: 2 Mbps Redundant HDLC Fieldbus
Functional Features
- Bumpless Transfer: Ensures smooth transition between automatic and manual control modes without process disruption.
- Analog Tracking: Continuously tracks manual station outputs to prepare for automatic takeover.
- Electrical Isolation: Complete isolation between channels and the system bus.
- Diagnostic Capabilities: Supports wire break detection and module health reporting.
Application Scenarios
Widely used in critical control loops where operators need to manually adjust valves or pumps during startup, shutdown, or emergency conditions, such as boiler feedwater control and turbine speed governing.
Performance Parameters
- Output Load: Capable of driving up to 600Ω loop impedance.
- Signal Accuracy: Typical accuracy of ±0.1% of full scale.
- Response Time: Software-configurable digital filtering with response times under 10ms.
Material Composition
Industrial-grade flame-retardant plastic housing with conformal-coated PCBs. High-quality screw or crimp terminals ensure reliable long-term connections.
Structural Characteristics
Standard FBM form factor with clear channel identification and status LEDs. High-density backplane connector supports hot-swapping.
Working Principle
The AI channel reads the manual station’s position feedback, while the AO channel receives DCS setpoints. The module’s internal logic manages bumpless transfer by matching outputs during mode transitions.
Installation Requirements
Insert into a compatible FBM baseplate. Use shielded twisted-pair cables for analog signals, with shields grounded at the cabinet side only.
Precautions for Use
Verify signal types and terminal definitions before wiring. Never short-circuit the output loop. Place the node in “Maintenance Mode” in software before replacing the module.
