The Fisher Rosemount 39A8571X042-90 (COMMONX1-AA3) is a high-reliability serial interface card designed for the RS-485/RS-232 communication layers within the DeltaV and legacy PROVOX distributed control systems (DCS).
Product Parameters (Datasheet)
- Model Number: 39A8571X042-90
- Designation: COMMONX1-AA3
- Interface Type: Serial Communication (RS-232 / RS-485 selectable)
- Compatibility: Fisher Rosemount DeltaV / PROVOX Control Systems
- Protocol Support: Modbus RTU, Allen-Bradley DF1, and custom serial protocols
- Isolation: Galvanic isolation between system logic and field communication ports
- Baud Rate: Adjustable up to 19.2 Kbps (standard) or higher depending on software revision
- Connector Type: Multi-pin edge connector for backplane integration
- Status Indicators: Onboard LEDs for Transmit (TX), Receive (RX), and Hardware Fault
Country of Origin
This module was engineered and manufactured by Fisher-Rosemount (now Emerson Automation Solutions) in the USA, specifically for critical process control infrastructure.
Application Fields
The COMMONX1-AA3 serial interface is primarily used in:
- Refining and Petrochemical: Interfacing DCS controllers with gas chromatographs and tank gauging systems.
- Power Generation: Communicating with auxiliary PLC systems for water treatment or fuel handling.
- Pharmaceutical: Connecting to precision weighing scales and environmental monitoring sensors.
- Pulp and Paper: Managing data exchange between various section controllers on a paper machine.
Product Usage Instructions
- Hardware Configuration: Set the onboard jumpers or DIP switches to define the communication standard (RS-232 vs RS-485) and station address before insertion.
- Installation: Insert the card into the designated I/O slot of the controller rack. Ensure the card is fully seated and the retaining screws are tightened.
- Software Setup: Within the DeltaV Explorer or PROVOX configuration environment, define the serial port parameters including baud rate, parity, and data bits.
- Wiring: Use high-quality shielded twisted-pair (STP) cabling for RS-485 runs to minimize electromagnetic interference.
- Diagnostics: Use the system diagnostic tools to monitor “Retries” and “Checksum Errors” to ensure the integrity of the serial link.
Product Technical Description
Technically, the 39A8571X042-90 functions as a communications co-processor. It offloads the task of managing serial timing and protocol framing from the main controller CPU, ensuring that process control loops remain deterministic. The COMMONX1-AA3 architecture is designed for “hot-plug” environments, allowing for module replacement without shutting down the entire rack, provided the system configuration supports redundant I/O.
Q&A (Common Questions)
Q: Can this module support Modbus TCP/IP? A: No, this is a serial-based module (RS-232/485). For Ethernet-based protocols, an Emerson VIM (Virtual I/O Module) or a dedicated Ethernet card is required.
Q: What does the “-90” suffix indicate? A: This usually refers to a specific hardware revision or a conformally coated version designed for harsh environments containing corrosive gases.
Q: Why is my RX LED blinking but the DCS shows “No Data”? A: This often indicates a parity or baud rate mismatch. The card is physically receiving signals, but the logic cannot decode the frames correctly.
Q: Is this card compatible with newer DeltaV M-series controllers? A: It is primarily designed for legacy S-series or PROVOX migrations. Check your DeltaV software version for compatible hardware drivers.
Similar Model Recommendations
- Fisher Rosemount 39A8571X012 (Standard Serial Variant)
- Emerson DeltaV 12P0510X132 (M-Series Serial Card)
- Fisher Rosemount 39A8551X022 (Analog Input Module)
- Rosemount 39A8571X052 (Enhanced Communication Revision)
- Fisher Rosemount 12P0162X022 (Processor Interface Card)
For technical support or pricing on the Fisher Rosemount 39A8571X042-90, please visit our industrial automation product portal.
