Overview
Manuals
Core Technical Specifications
Network Integration & Lifecycle
Features:
- It features 16 isolated input channels operating at a standard nominal voltage of 24 Vdc
- The 24 Vdc contact wetting voltage can be drawn from the internal control chassis power loop or injected via an external industrial power supply
- Every channel features a high-voltage optical isolation design (typically up to 1500V AC)
The 9905-971 is a high-reliability discrete input module in Woodward's LINKnet 9900 series, designed for steam turbines, gas turbines, and various demanding industrial control systems. Its core function is to provide high-density digital signal acquisition, capable of simultaneously receiving up to 16 (up to 24 in some configurations) independent 24Vdc switching signals. This module is primarily used for real-time monitoring of critical digital signals from field devices, such as the position status of switches, relays, and valves, as well as system alarms. These statuses are then transmitted in real-time to the master controller (e.g., a NetCon controller) via the LINKnet network, enabling status feedback in industrial closed-loop control.
Furthermore, this module features excellent dynamic event logging and high-availability diagnostics. To meet the stringent requirements of industrial safety and fault-tolerant systems, the 9905-971 integrates a high-precision timestamp function, capable of accurately recording input events with a resolution of 1 millisecond (ms), providing a precise data link for the system's Sequential Event Recording (SOE). Meanwhile, the module also integrates a potential fault detection mechanism, which can actively detect potential device faults or channel anomalies in the circuit around the clock without interfering with normal system control, thereby effectively preventing unexpected system shutdowns caused by a single undetected fault.
The 9905-971 Woodward LINKnet discrete input module may still be available for purchase and support from Moore Automated Company beyond End-Of-Life (EOL) by the manufacturer (OEM).
Woodward 9905-971 LINKnet discrete input module datasheet(manual), Link
Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description. All prices are shown in USD.
1.Power Requirements: Reliably operates on 18–32 Vdc power with a maximum power consumption of 14.2 watts.
2.Data Refresh Performance: Captures state changes with a precise update cycle of 1 millisecond resolution. This high-speed capability enables the system to accurately sequence events in fault conditions.
3.Potential Fault Detection: Features internal predictive diagnostics and readback circuitry. It periodically tests internal signal paths and outputs to detect hidden hardware faults before they are actually triggered in emergency execution cycles.
4.Physical Interface: Employs a slide-in slot design for secure locking into the main control chassis. It is equipped with front panel mounting screws and high-strength clips to ensure safe maintenance procedures.
The 9905-971 module uses an early LON-based network protocol, communicating with the host controller via a single shielded twisted-pair cable. For network addressing, engineers need to manually adjust two onboard rotary switches on the module housing to define its position identifier (nodes 1 to 60) relative to the host system configuration file.
Lifecycle Notes: This traditional LON-based component has been largely replaced in modern automation designs by CANopen-based LINKnet HT series (e.g., model 8200-1204). However, legacy systems using CPU040, CPU060, or NT processing architectures still support the 9905-971 module without requiring a full hardware migration.
