The WOODWARD 9905-971 Rev(K), also cataloged as the 9905-971 Rev(K) Discrete Input Module, operates as a dedicated hardware component for high-speed contact state monitoring and digital signal acquisition within prime mover and control network platforms.

Hardware Specifications

Actuator Loop Feedback Response and Thermal Dissipation Profiles

The discrete input card processes contact transitions across dual active/active redundant control channels within a sub-5 ms response window. This parallel signal processing ensures deterministic loop synchronization and maintains high actuator loop feedback response during dynamic control cycles. Onboard power regulation components radiate heat through thermal heat sink dissipation profiles integrated into the 150 x 100 x 40 mm chassis, sustaining continuous operation across the -40 to 85 deg C thermal envelope.

Frequently Asked Questions

Q: How does the dual-channel active/active redundancy function during a single channel fault?

A: Both channels process input signals simultaneously. If one channel encounters a signal loss or internal hardware fault, the secondary channel maintains uninterrupted communication over Modbus TCP or OPC UA without switching latency.

Q: What mechanisms protect internal digital circuits against external line noise?

A: High-speed optocouplers isolate incoming 24 VDC field contact lines from the internal processing unit, while digital filtering suppresses mechanical contact bounce noise.

Field Installation Guidelines

1. Mount the 1.45 kg enclosure onto a standard DIN rail or panel surface inside an IP54-rated metal protective cabinet.
2. Connect the 24 VDC main power supply to designated terminals using 18 to 14 AWG conductors, ensuring voltage limits remain within 21.6 to 26.4 VDC.
3. Wire discrete field inputs using shielded twisted-pair cables, grounding the cable shield at the main panel earth ground point only.
4. Establish Modbus TCP or OPC UA network links via Ethernet interface lines, maintaining proper conduit separation from high-voltage AC cables.
5. Provide a minimum clearance of 50 mm surrounding the module frame to ensure adequate thermal heat sink dissipation under 5 Grms vibration conditions.