Woodward 9905-973 LinkNet RTD Input Module

Key Technical Specifications

Technical verification note: Public Woodward documentation confirms the LinkNet family and its RTD-input variants, but the sources reviewed do not provide enough OEM-level information to safely state the exact channel count, RTD resistance range, accuracy, or terminal assignment for 9905-973 specifically. Those values should be confirmed from the module label and applicable Woodward manual before installation.

Product Introduction

The Woodward 9905-973 belongs to the LinkNet family of distributed I/O hardware used with legacy Woodward control systems. LinkNet nodes communicate with the associated controller through a LON-based network and provide dedicated field-signal interfaces for turbine and engine control applications.

For a 9905-973 replacement, the complete part number is important. Verify the installed module’s input type, channel configuration, network connection, terminal arrangement, and controller compatibility before treating another LinkNet module as a substitute.

9905-973

9905-973

Installation & Configuration Guide

Stage 1: Pre-Installation Preparation — About 10 Minutes

⚠️ Safety First: Place the turbine or engine control system in the approved maintenance state. Apply the site’s LOTO procedure before disconnecting the LinkNet module.

Tools Required:

• ESD wrist strap
• Digital multimeter
• Appropriate screwdriver
• Wire labels
• Smartphone/camera
• Approved Woodward system documentation

Data Backup:

1. Record the complete 9905-973 part number and revision.
2. Photograph the module and all terminal connections.
3. Record the LinkNet node address.
4. Identify every connected temperature channel.
5. Record the corresponding field-device tags.
6. Photograph the network connection and cable routing.
7. Retain the original module until commissioning is complete.

Stage 2: Removing the Old Module — About 5–10 Minutes

1. Confirm the controlled equipment is in a safe maintenance state.
2. Isolate the module’s 24 VDC supply.
3. Verify the supply is de-energized with a multimeter.
4. Label each field connection.
5. Photograph the wiring before disconnecting it.
6. Disconnect the field wiring carefully.
7. Disconnect the LinkNet communication connection.
8. Release the module from its mounting arrangement.
9. Inspect the connector and mating interface for damage or contamination.

⚠️ Do not rely on wire colors or memory. Legacy installations are often modified during years of service.

Stage 3: Installing the New 9905-973 — About 10 Minutes

1. Verify the exact 9905-973 part number.
2. Compare the replacement with the removed module.
3. Confirm connector locations and mechanical dimensions.
4. Install the module in the original approved location.
5. Reconnect the LinkNet network connection.
6. Reconnect each field circuit according to the original photographs and wiring diagram.
7. Verify the node/address configuration.
8. Secure all terminals.
9. Inspect for loose conductors before energizing.

Configuration Clone — Critical:

• LinkNet node address
• Field-channel assignment
• Sensor type
• Controller I/O mapping
• Alarm configuration
• Existing temperature scaling
• Network configuration

Self-Checklist:

• Correct 9905-973 verified
• Node address documented
• Field wiring matched
• Network cable secured
• Sensor assignments verified
• Terminals tightened
• Original configuration available

Stage 4: Power-On & Testing — About 10–20 Minutes

1. Perform a complete visual inspection.
2. Verify the 24 VDC supply.
3. Energize the LinkNet module according to the approved procedure.
4. Check module status indications.
5. Confirm communication with the Woodward controller.
6. Verify the module is recognized at the correct network address.
7. Check each connected temperature channel.
8. Compare displayed values with an independent temperature reference where practical.
9. Verify alarm status and channel mapping.
10. Complete the site’s approved functional test before returning the control system to normal service.

⚠️ Do not stop at a communication check. A LinkNet module can communicate correctly while an individual field channel is incorrectly wired or assigned.

Frequently Asked Questions (FAQ)

Q1: What is the Woodward 9905-973?
The 9905-973 is a legacy Woodward LinkNet distributed I/O component associated with temperature/RTD signal acquisition. The exact channel configuration should be confirmed from the installed unit and applicable Woodward documentation.

Q2: Is 9905-973 part of the LinkNet system?
Yes. The part number belongs to the Woodward LinkNet hardware family. LinkNet uses a LON-based communication architecture for distributed control-system I/O.

Q3: Is 9905-973 interchangeable with another LinkNet RTD module?
Not automatically. Even when two modules perform similar temperature-input functions, their channel count, sensor range, terminal configuration, addressing, and controller mapping may differ. Verify the complete part number before substitution.

Q4: Is the 9905-973 obsolete?
It should be treated as legacy hardware. Woodward has discontinued the original LON-based LinkNet architecture for new applications, so availability of individual modules depends largely on remaining inventory and specialist spare-parts channels.

Q5: Can I hot-swap the 9905-973?
Do not assume hot-swapping is permitted. Follow the specific Woodward control-system maintenance procedure for the installed hardware and cabinet configuration.

Q6: What should I verify before buying a 9905-973?
Confirm the complete 9905-973 number, hardware revision, connector arrangement, field-input type, LinkNet node configuration, and physical condition. For a refurbished unit, request the test procedure and test report.

Q7: Why is exact identification particularly important for this part?
The LinkNet family contains several specialized I/O modules with similar physical formats. A visually similar replacement can communicate with the network but still provide the wrong field interface. For an operating turbine or engine, verify the I/O function and channel mapping before installation, not merely the mechanical fit.