Foxboro FBM204

Technical Specifications:

• Input Channels: 4 × 20 mA DC analog inputs
• Input Compatibility: 4–20 mA transmitters or self-powered 20 mA sources
• Output Channels: 4 × 20 mA DC analog outputs
• Output Range: 0 to 20 mA per channel
• Isolation: Galvanic isolation channel-to-channel and channel-to-ground
• Conversion Technology: Sigma-delta data conversion
• Power Supply: 24 VDC (+5%, -10%), redundant support
• Operating Temperature: -40°C to +85°C
• Protection Rating: IP67
• Typical Power Consumption: 1.5 W
• Environmental Class: Class G3 (harsh environment) Functional Features:
• Configurable conversion time and Rate of Change Limits
• Per-channel fail-safe configuration (Hold/Return)
• Support for DPIDA control blocks
• Compatible with termination assemblies for local/remote wiring
• Output bypass station support for maintenance continuity
• Rugged compact design for harsh conditions Application Scenarios:
• Analog signal processing in Class G3 harsh industrial environments
• Offshore platform, petrochemical and chemical process control
• Distributed field I/O stations with limited installation space
• High-precision closed-loop analog control loops Structural Features:
• Compact rugged metal housing with heat dissipation fins
• Standard rack mounting for Compact 200 Series subsystem
• Integrated redundant fieldbus interface
• Front panel LED channel status indicators Operating Principle: The module performs sigma-delta A/D conversion on input current signals from field sensors and transmits digital data to the control system via redundant fieldbus. For outputs, it receives digital commands and converts them to 0–20 mA analog signals via D/A conversion to drive actuators. All channels are electrically isolated to eliminate ground loop interference. Installation Requirements:
• Install in Compact 200 Series I/O rack or dedicated enclosure
• Ensure adequate ventilation and temperature control
• Use matched termination assemblies for field wiring
• Verify 24 VDC power supply meets tolerance requirements Usage Notes:
• Use output bypass station during module replacement to maintain process continuity
• Perform periodic insulation resistance tests
• Do not expose to direct water spray despite IP67 rating