The Woodward 9905-973 is a high-reliability, 8-channel relay output module designed as a core component of the LinkNet distributed I/O system. It provides precise, remote-controlled switching for industrial actuators, valves, alarms, and other auxiliary equipment. Engineered for mission-critical reliability, this module is widely utilized in sectors requiring robust performance, such as power generation, marine propulsion, and heavy-duty turbine management systems.
Product Parameters
Product Model: 9905-973 System Family: LinkNet Distributed I/O Function: 8-Channel Relay Output Module Operating Voltage: 24V DC nominal Output Type: 8 Independent Form C (SPDT) Relay Contacts Communication Interface: LinkNet Serial Bus (RS-485 based) Operating Temperature: -25°C to +70°C Mounting: DIN-rail mount Weight: 0.65 kg Original Manufacturer: Woodward, Inc. Origin: USA / Global Manufacturing
Technical Datasheet Overview
The 9905-973 serves as a distributed actuator interface, receiving command instructions from a primary Woodward controller via the LinkNet bus and converting these signals into physical relay switching operations.
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Flexibility: The 8 channels allow for independent control of various auxiliary devices.
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Safety: Each relay output is galvanically isolated, protecting the sensitive LinkNet bus from potential electrical surges or faults originating in the field-side wiring.
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Diagnostics: Includes onboard health monitoring that communicates relay status and bus integrity back to the master controller, facilitating rapid fault detection.
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Durability: Specifically built to withstand high-vibration environments, typical of turbine and engine compartments.
For comprehensive technical documentation and system architecture details, please visit the Woodward 9905-973 product page.
Application Fields
This module is a staple in industries where continuous uptime and precision are non-negotiable:
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Gas & Steam Turbines: Managing auxiliary systems like fuel shutoff valves, lube oil pumps, and start/stop control logic.
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Marine Power Systems: Coordinating generator set synchronization, circuit breaker control, and alarm signaling.
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Compressor Control: Executing staging and loading/unloading sequences for industrial-scale air and gas compressors.
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Industrial Automation: General-purpose distributed control where reliable remote relay switching is required over long cable distances.
Product Operating Instructions
Installation must be performed by authorized personnel familiar with Woodward control architectures. Ensure the LinkNet bus is properly terminated at both ends of the segment to prevent signal reflections. Secure the module onto the DIN rail, then connect the 24V DC power supply to the designated terminals. Using the primary controller software, assign a unique LinkNet node address to the module. Once integrated, perform a functional test using the “Force” command in the control software to actuate each relay individually, verifying that the corresponding field device operates as expected.
Frequently Asked Questions (Q&A)
What is the maximum contact rating for the relays? The relays are typically rated for 5A at 24V DC or 120/240V AC; however, always verify the specific datasheet for your installation to avoid exceeding inductive load limits. How do I troubleshoot a communication error on the LinkNet bus? Check the status LEDs on the module; if the “Comm” LED is flashing or off, verify the integrity of the shielded twisted-pair communication cable and ensure the bus is terminated with a 120-ohm resistor. Can this module be used without a main Woodward controller? No, LinkNet modules are proprietary and require a Woodward master controller to interpret and send the necessary control protocol. What is the difference between this and other 9905-xxx series modules? The 9905-973 is specifically an 8-channel relay module; other models in the series may offer analog input/output capabilities, different channel densities, or digital input functionality.
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