Woodward 5501-470 CPU Module – Real-Time Control Processor for Compressor Anti-Surge Systems

Brand WOODWARD

Model Woodward 5501-470

Product Overview

The Woodward 5501-470 is a central processing unit module for the Woodward NetCon and MicroNet digital control platforms, serving as the computational heart of turbine, compressor and large-engine control systems. Catalogued in the field as the NetCon CPU_040 module in the “without LL memory” configuration, the Woodward 5501-470 is a 3U-format plug-in processor board that executes the control application directly on the board, manages the backplane bus, schedules I/O exchanges across the chassis and handles the communication links that connect the control rack to the plant DCS or HMI. Understanding the “W/O LL MEMORY” designation matters at specification time: this variant carries standard application and non-volatile storage for firmware, configuration and operating data, but it is not fitted with the low-level memory expansion found on its uprated siblings, so it is the correct choice for applications whose memory map is already served elsewhere in the rack.

Architecturally, the Woodward 5501-470 is built around an industrial 32-bit microprocessor of the Motorola 68040 class and communicates with the rest of the chassis over a VMEbus backplane, which gives it the deterministic, low-latency data path that real-time governing requires. Power is drawn from the rack’s logic supply, typically 5 V DC derived by a MicroNet power supply module, and the board carries integrated EMI filtering so that switching noise from nearby contactors, drives and exciters does not corrupt its internal timing. Front-panel status LEDs and a serial service port give maintenance personnel direct visibility into processor state, and on-board hardware and software watchdogs continuously supervise logic power and microprocessor activity.

The real significance of the Woodward 5501-470 is its position in the operational risk profile of a plant. It is the module that closes the speed, load, temperature and anti-surge control loops; when it fails, the control system stops thinking even though the I/O cards are still healthy. Because the NetCon and first-generation MicroNet platforms are now legacy hardware with a large installed base in power generation, oil and gas compression and marine propulsion, the Woodward 5501-470 is one of the highest-value spares an operator can hold, and a verified unit on the shelf is frequently the difference between a short planned replacement and an extended outage.

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Description

Technical Specifications

Parameter Name	Parameter Value
Product Model	5501-470
Manufacturer	Woodward (Woodward Governor Company)
Product Type	CPU / Central Processor Module (NetCon CPU_040)
Configuration	Without LL (Low-Level) Memory
Processor	Industrial 32-bit microprocessor, Motorola 68040 class
Memory	470 KB non-volatile storage for application, configuration and operating data
Platform Compatibility	Woodward NetCon 5000 / 5000B, MicroNet and MicroNet Plus chassis
System Architecture	Simplex, dual and TMR (triple modular redundant) configurations supported
Bus Interface	VMEbus high-speed backplane
Service Interface	9-pin D-Sub serial (RS-232) for programming and diagnostics; Ethernet on later revisions
Supply Voltage	5 V DC via rack backplane (from MicroNet power supply such as 5501-467)
Power Consumption	Approximately 8–10 W
Diagnostics	Software and hardware watchdog supervision, LED status indication, manual reset
EMC Protection	Integrated EMI filtering on board
Protection Class	IP20, conformal coated PCB for harsh environments
Operating Temperature	-40 °C to +85 °C (verify against your revision documentation)
Storage Temperature	-55 °C to +95 °C
Humidity	0 to 100% RH, non-condensing
Vibration / Shock	10–2000 Hz at 0.015 in amplitude / 15 g, 11 ms half-sine
Form Factor	3U Eurocard plug-in module, MicroNet rack slot
Weight	Approximately 0.7–1.0 kg
Available Revisions	Rev B, Rev D, Rev E (confirm compatibility with chassis and firmware)
Lifecycle Status	Discontinued / legacy – new surplus, refurbished and exchange units only
Certifications	CE, UL, ATEX, DNV, ABS, LRS (hazardous-location approvals, revision dependent)
Country of Origin	USA

Main Features and Advantages

Deterministic real-time execution on board:

The Woodward 5501-470 runs a real-time operating system locally, so speed governing, load sharing, fuel limiting and sequencing logic are executed on the CPU itself rather than on an external supervisory computer. For a turbine or compressor, that distinction is critical: control response stays deterministic even if the plant network is congested or the HMI workstation is offline, and the machine continues to be governed safely through communication disturbances that would paralyse a less autonomous architecture.

VMEbus backplane for low-latency I/O:

By exchanging data with the chassis I/O modules over a VMEbus backplane, the Woodward 5501-470 keeps the delay between a field measurement and the corresponding actuator command short and predictable. That predictable scan behaviour is what allows tight control loops to be tuned without margin-stealing software filters, and it is why this processor remains trusted in applications where a few milliseconds of additional lag would show up as speed instability or surge margin erosion.

Built for electrically hostile environments:

Control cabinets beside generators, exciters and large motor starters are among the noisiest places in a plant. The Woodward 5501-470 addresses that reality with integrated EMI filtering, a conformal coated board that resists salt spray, humidity and conductive dust, and a mechanical design rated to 15 g shock and continuous vibration from 10 to 2000 Hz. Combined with a -40 °C to +85 °C operating range, the Woodward 5501-470 is specified for service on offshore platforms, desert compressor stations and unheated turbine hall enclosures alike.