WOODWARD 9905 Series Modules | 9905-792 Speed Control Board

Technical Dossier

Product Details And Specifications

WOODWARD 9905 Series: Comprehensive Module Range and Technical Overview

The WOODWARD 9905 Series represents a mature, field-proven platform deployed across global heavy industry sectors including petrochemical refineries, nuclear power stations, offshore platforms, and large-scale thermal power generation facilities. Originally engineered as a dedicated turbine and generator control system, the 9905 Series established WOODWARD's position as a primary supplier of speed governing and load-sharing control hardware. Installations of this series remain operational across hundreds of baseload power plants in North America, Europe, and Asia-Pacific, where replacement of the control infrastructure is cost-prohibitive. The 9905 architecture is characterized by modular backplane construction, deterministic scan-cycle execution, and hardware-level redundancy options that meet the reliability requirements of continuous-process industries. Its installed base in critical rotating machinery applications — gas turbines, steam turbines, hydro governors, and diesel gensets — makes long-term spare parts availability a primary operational concern for plant maintenance engineers.

The Evolution of 9905 Architecture

The WOODWARD 9905 Series was introduced as a successor to earlier analog governing platforms, transitioning plant operators from relay-logic and analog PID controllers to a digital, microprocessor-based control environment. Early 9905 variants used proprietary serial backplane communication with fixed-function I/O modules. Mid-generation revisions introduced expanded analog input resolution (12-bit to 16-bit ADC), increased the number of addressable I/O slots per chassis, and added support for MODBUS RTU communication over RS-485 for SCADA integration. Later production runs incorporated isolated discrete I/O to address ground-loop interference issues common in high-voltage switchyard environments. The 9905 Series has entered the mature/end-of-life phase of its product lifecycle. WOODWARD has transitioned its current turbine control portfolio to the MicroNet Plus and 505E platforms. As a result, 9905 Series hardware is no longer manufactured to order. All procurement is sourced from surplus inventory, tested pull-outs, and factory-refurbished stock. For plant operators committed to maintaining 9905-based systems, a structured lifecycle extension strategy — including critical spare identification, board-level repair capability, and firmware version locking — is the standard industry approach.

9905 Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly sourced components within the WOODWARD 9905 Series. Each entry reflects the module's primary functional role within the control system architecture.

9905-792: Speed control board; primary governing processor for turbine speed regulation and droop control.
9905-001: Analog input module; 8-channel, 4–20 mA process signal acquisition for turbine instrumentation.
9905-002: Discrete input module; 16-channel 24 VDC digital input for valve position and limit switch feedback.
9905-003: Discrete output module; 16-channel relay output for actuator command and alarm annunciation.
9905-004: Analog output module; 4-channel 4–20 mA output for valve positioner and speed reference signals.
9905-010: CPU processor board; main control execution unit, hosts application firmware and scan-cycle management.
9905-011: Redundant CPU module; hot-standby processor for bumpless transfer in critical turbine applications.
9905-020: Power supply module; 24 VDC regulated backplane power, 10 A continuous output rating.
9905-021: Redundant power supply; parallel-redundant configuration for uninterrupted backplane voltage.
9905-030: MODBUS RTU communication adapter; RS-485 serial interface for DCS and SCADA data exchange.
9905-031: Ethernet communication module; 10/100 Mbps TCP/IP gateway for plant historian and remote monitoring.
9905-040: Speed/frequency input module; magnetic pickup and proximity probe signal conditioning, dual-channel.
9905-041: Overspeed detection module; hardware-level trip relay, independent of CPU scan cycle, SIL-rated.
9905-050: Load-sharing module; isochronous load sharing across parallel generator sets via droop compensation.
9905-060: Backplane chassis, 8-slot; base mounting rack for 9905 Series module population.
9905-061: Backplane chassis, 16-slot; extended rack for large turbine control configurations.
9905-070: Battery backup module; maintains volatile RAM and real-time clock during power interruption.
9905-080: Thermocouple input module; 8-channel Type K/J/T thermocouple with cold-junction compensation.
9905-090: RTD input module; 4-channel PT100/PT1000 resistance temperature detector signal processing.

Sourcing Hard-to-Find & Obsolete 9905 Parts

DriveKNMS maintains a dedicated inventory program for end-of-life WOODWARD 9905 Series components. As WOODWARD has discontinued active production of this platform, the primary sourcing channels are decommissioned plant equipment, authorized surplus distributors, and board-level refurbishment of failed units. DriveKNMS operates a global procurement network that tracks 9905 Series availability across North America, Europe, and Asia. For obsolete modules where no surplus stock exists, DriveKNMS provides component-level board repair services, including FPGA re-programming, capacitor replacement, and conformal coating restoration. All sourced units are accompanied by full traceability documentation. Lead times for critical modules such as the 9905-792, 9905-010, and 9905-020 are typically 3–10 business days from confirmed order. Emergency same-day dispatch is available for in-stock items. Customers are encouraged to submit a complete bill-of-materials for their 9905 installation to enable proactive spare parts planning.

Quality Control for the 9905 Range

The WOODWARD 9905 Series employs a proprietary backplane bus architecture with time-multiplexed data transfer between the CPU and I/O modules. Standard incoming inspection procedures at DriveKNMS include visual inspection for physical damage, corrosion, and component substitution; powered functional testing on a dedicated 9905 test chassis replicating the original backplane electrical environment; firmware version verification against the customer's installed revision; and burn-in testing under simulated load conditions for a minimum of 24 hours. Speed control boards such as the 9905-792 undergo additional validation: magnetic pickup signal simulation across the full operating frequency range (0–10,000 Hz), actuator output linearity verification, and overspeed trip relay response-time measurement. Communication modules are tested for protocol compliance using MODBUS master simulation tools. All units that pass the full test protocol are issued a DriveKNMS test certificate with recorded test parameters and technician sign-off.

© 2026 DriveKNMS. All trademarks belong to their respective owners. Specifications are for reference only and subject to change without notice. Verify all parameters against official documentation before installation.