Woodward LinkNet-HT Discrete I/O Modules 8200-1204 & 8200-1205
Woodward LinkNet-HT Discrete I/O Modules: 8200-1204 & 8200-1205
The Woodward 8200-1204 and 8200-1205 are high-density, distributed I/O modules belonging to the LinkNet-HT™ family.
These modules are designed to expand the digital “senses” and “actions” of Woodward’s primary control systems (such as the MicroNet Plus, Peak200. or 505XT).
8200-1204: A Discrete Input (DI) module used to monitor switches, contacts, and status signals.
8200-1205: A Discrete Output (DO) module used to trigger relays, solenoids, and indicators.
Technical Parameter Table
| Feature | 8200-1204 (Discrete Input) | 8200-1205 (Discrete Output) |
| Channels | 16 Discrete Inputs | 16 Discrete Outputs |
| Input/Output Type | Optically Isolated / Voltage Sensing | Sinking (Open Collector) |
| Input Voltage Range | 18–32 Vdc (Internal/External) | Max 32 Vdc |
| Output Current | N/A | 500 mA per channel (continuous) |
| Communication | Dual CANOpen (LinkNet-HT) | Dual CANOpen (LinkNet-HT) |
| Power Supply | 18–36 Vdc | 18–36 Vdc |
| Operating Temp | –40 °C to +70 °C | –40 °C to +70 °C |
| Environment | Class G3 Conformal Coating | Class G3 Conformal Coating |
| Hazardous Rating | ATEX/IECEx Zone 2; Class I Div 2 | ATEX/IECEx Zone 2; Class I Div 2 |
Product Advantages and Features
Simplified Field Wiring: These modules can be mounted directly on the turbine skid, allowing dozens of status points to be sent back to the control room over a single pair of CAN wires.
High Reliability: Features dual-redundant CAN ports. If one communication cable is severed, the module continues to function via the secondary path.
Rugged Protection: Class G3 conformal coating ensures the internal circuitry is immune to the corrosive effects of salt air, humidity, and sulfur gases ($H_{2}S$).
Advanced Diagnostics: * The 8200-1204 detects contact chattering and input health.
The 8200-1205 features “Read-Back” capability to verify the output driver is actually in the correct state.
Density: Packs 16 channels into a slim, DIN-rail mounted footprint, saving significant space in control cabinets.
Unique Product Description
The Woodward 8200-1204 and 8200-1205 are the “nervous system” extensions of a turbine’s brain. While the main controller focuses on complex math and PID loops,
these modules handle the high-volume traffic of digital signals—monitoring every limit switch and firing every solenoid.
Their unique LinkNet-HT architecture allows for a “daisy-chain” configuration, meaning you can add 16 or 160 points of I/O with minimal impact on wiring complexity or system cost.
Application Cases
Turbine Sequencing: Monitoring “Ready to Start,” “Turning Gear Engaged,” and “Oil Pressure OK” signals (8200-1204).
System Alarming: Controlling local annunciator panels or beacon lights to alert operators of specific fault conditions (8200-1205).
Solenoid Control: Directly driving the trip solenoids or isolation valves in the turbine’s hydraulic or steam circuit (8200-1205).
Remote Status Monitoring: Tracking the open/closed state of manual isolation valves across a large industrial plant.
Installation and Maintenance
Addressing: Use the onboard rotary switches to set a unique Node ID for each module on the LinkNet-HT network before powering up.
Mounting: Snap onto a standard 35mm DIN rail. For high-vibration environments, use end-stops to secure the modules.
Termination: Always ensure a 120 $\Omega$ resistor is placed at the physical ends of the CAN network to prevent data reflections and communication errors.
Replacement: The modules are “plug-and-play” with removable terminal blocks, allowing for rapid replacement without disconnecting individual field wires.
Other Models in the Same Series
Model Function Channels
8200-1200 RTD Input Module 8 Channels
8200-1201 Thermocouple Input Module 8 Channels
8200-1202 Analog I/O (4-20mA) 8 In / 2 Out
8200-1300 505D Simplex Controller Main Governor