Product Detailed Description
Function:
Converts digital commands from the control system (DCS) into analog output signals (e.g., 0-20 mA DC, 4-20 mA DC, or voltage signals) to control field devices like valves, actuators, variable speed drives, and other instrumentation.
Provides galvanic isolation between individual output channels and between channels and ground, which is essential for protecting sensitive electronics from ground loops, noise, and potential differences, especially in harsh industrial environments.
Many models support redundancy, allowing for continuous operation even if one module fails, thereby increasing system availability.
Often compatible with HART (Highway Addressable Remote Transducer) protocol, enabling digital communication with smart field devices for configuration, diagnostics, and additional process information.
Features:
Channel Isolation: Each output channel is individually isolated, preventing cross-talk and ensuring signal integrity.
Robust Design: Typically housed in a rugged, often extruded aluminum, enclosure for physical protection and suitability in harsh environments (e.g., Class G3).
High Accuracy: Designed for precise control with high resolution and low linearity errors.
Diagnostics: Built-in diagnostic capabilities to monitor module health and report faults (e.g., open circuit, short circuit).
Redundancy Support: Many modules can be configured in redundant pairs to enhance system availability and minimize downtime during module replacement or failure.
Hot-Swappable: In redundant configurations, modules can often be replaced without interrupting field output signals, power, or communication, facilitating easier and safer maintenance.
Compatibility: Designed for seamless integration with Foxboro DCS systems (e.g., I/A Series, Foxboro Evo).
Configurable Outputs: Allows for configurable output ranges and fail-safe/fallback options (e.g., drive output to 0 mA on failure).
Product Parameters (Typical for Isolated Analog Output Modules like FBM237, FBM204)
Number of Channels: Typically 4, 8, or 16 isolated output channels.
Output Signal Type: Commonly 0-20 mA DC or 4-20 mA DC. (Some models may offer voltage outputs).
Accuracy (Analog): High accuracy, typically ±0.03% to ±0.05% of span (including linearity).
Accuracy Temperature Coefficient: Typically ±50 ppm/°C.
Output Load: Specified maximum load resistance (e.g., 750 Ω maximum for 20 mA outputs).
Resolution: High resolution, e.g., 13 bits.
Isolation: Galvanic isolation between channels and to earth (ground). Withstands significant AC voltage (e.g., 600 VAC for 1 minute) between channels and ground.
Loop Power Supply Protection: Each channel often includes channel-to-channel galvanic isolation, current limiting, and voltage regulation.
Output Processing Delay: Typically low, e.g., 30 ms maximum.
Input Voltage: Typically 24V DC.
Power Consumption: Varies by module (e.g., P0916NB has max 8.5W).
Operating Temperature: Wide range, e.g., 0°C to +60°C (+32°F to +140°F), sometimes -40°C to +85°C for specialized versions.
Physical Design: Compact modular design.
Compatibility: Foxboro DCS (e.g., I/A Series, Foxboro Evo).
Certifications: UL, cUL, CE, etc.
Product Advantages
Enhanced System Reliability and Availability: Isolation protects against noise and ground loops, and redundancy options ensure continuous operation even with module failures.
Increased Safety: Isolation prevents hazardous voltages from affecting other parts of the system or personnel.
Precise Control: High accuracy and resolution allow for fine-tuned process control, leading to better product quality and operational efficiency.
Reduced Interference: Channel-to-channel isolation minimizes electrical interference, ensuring clean and stable signals.
Simplified Maintenance: Hot-swappable design and easy replacement reduce downtime during maintenance or troubleshooting.
Robustness: Designed for harsh industrial environments, ensuring long-term durability and performance.
Seamless Integration: Fully compatible with Foxboro DCS platforms, streamlining system design and configuration.
HART Compatibility: Enables advanced diagnostics and asset management for smart field devices.
Precautions
Correct Selection: Choose the appropriate module based on the required number of channels, output signal type, load requirements, accuracy needs, and redundancy strategy.
Proper Installation: Follow the manufacturer's installation guidelines meticulously, including correct mounting in a suitable enclosure (especially for hazardous locations) and proper earthing/grounding.
Wiring Practices: Use appropriate shielded cables and follow best practices for wiring to minimize noise and interference. Ensure correct polarity for DC outputs.
Environmental Conditions: Operate the module within its specified temperature and humidity ranges. Protect it from excessive vibration, shock, and corrosive atmospheres.
Power Supply: Ensure a stable and correctly rated power supply is provided, often with redundancy for critical applications.
Safety Interlocks: While these modules provide isolation, always design safety instrumented functions with appropriate safety interlocks and certified safety systems as per relevant safety standards (e.g., IEC 61508, IEC 61511).
Firmware and Software Compatibility: Ensure the module's firmware is compatible with the version of the Foxboro DCS software being used.
Product Applications
Foxboro Isolated Output Modules are widely used in critical industrial process control applications across various sectors, including:
Oil and Gas: Controlling valves, pumps, and other instruments in refineries, pipelines, and offshore platforms.
Chemical Processing: Regulating flow rates, temperatures, and pressures in chemical reactors and processing units.
Power Generation: Controlling turbine governors, boiler feedwater pumps, and other balance-of-plant equipment in power plants.
Pulp and Paper: Regulating motor speeds, valve positions, and other process variables.
Water and Wastewater Treatment: Controlling pumps, chemical dosing systems, and aeration equipment.
Mining and Metals: Automation of crushing, grinding, and refining processes.
Pharmaceutical: Precise control of batch processes, temperature, and pressure in pharmaceutical manufacturing.
General Manufacturing: Any application requiring reliable and isolated analog control signals to field devices from a DCS or control system.
