Woodward MicroNet ™ Analysis and Application of Simplex and Plus Digital Control Systems

Woodward MicroNet ™  Analysis and Application of Simplex and Plus Digital Control Systems

Introduction

Woodward MicroNet ™  Digital control system is a high-performance and high reliability solution for industrial power control field. This series of products is widely used for precise control and protection of power devices such as gas turbines, steam turbines, diesel engines, and water turbines. The MicroNet Simplex and MicroNet Plus control systems covered in this manual have flexible configuration options that support diverse requirements ranging from simple applications to complex redundant systems. As one of Woodward's core products, the MicroNet platform is renowned in the fields of energy, marine, and industrial automation for its outstanding real-time performance, modular design, and extensive support for industrial communication protocols.

This article is based on the complete content of Woodward's official product manual 26166V1 (revised version V, released in August 2024), aiming to provide in-depth technical analysis, configuration guidelines, and application recommendations to help engineers, technicians, and system integrators fully understand and efficiently apply the control system.

1、 System Overview and Product Architecture

1.1 MicroNet Control System Family

MicroNet Simplex and MicroNet Plus are digital controllers based on 32-bit microprocessors that can be programmed to adapt to various application scenarios. The control system provides comprehensive functions such as high-speed control, system sequence control, auxiliary system control, surge control, monitoring and alarm, and station control. This platform provides Simplex, Redundancy, and Triple Modular Redundancy (TMR) configurations, and this manual mainly covers Simplex and Redundancy configurations.

The system adopts Woodward's unique rate group structure to ensure that control functions can execute deterministically according to the rate group defined by the application engineer. The critical control loop can complete processing within 5 milliseconds, while secondary code is assigned to slower rate groups. This structure ensures that the dynamic characteristics of the system will not change due to the addition of additional code, and the control always has certainty and predictability.

1.2 System Configuration and Compatibility

The MicroNet platform is built around the VME chassis and CPU modules, with the CPU module located in the first active slot of the VME chassis and all I/O modules inserted into the remaining slots. The MicroNet Plus chassis supports single CPU operation and dual CPU redundancy operation, with each chassis capable of accommodating up to 14 VME slots. The system can be expanded to multiple chassis using copper or fiber optic cables to meet additional I/O requirements.

The environmental specifications and compatibility information of the system are detailed in the corresponding appendix of Volume 2 of this manual, while information on non preferred and obsolete modules is included in Volume 3.

2、 Detailed explanation of MicroNet Plus system

2.1 Redundant Configuration

The MicroNet Plus control system provides a complete redundancy solution, achieving high availability through dual CPU modules. In a redundant system, two CPU modules run the same application, share access to I/O modules, and communicate with each other through the VME bus. A CPU module with good health becomes the system controller (SYSCON), while another one serves as a backup (STANDBY). When the main CPU fails, the backup CPU can seamlessly take over control.

The system supports multiple redundant configuration options:

Fully redundant: Both the host rack and expansion rack use redundant CPUs and RTN modules

Partial redundancy: Main CPU redundancy, expansion rack can use single RTN or redundant RTN

Simplex configuration: Single CPU operation, expansion rack using single RTN module

2.2 Power Supply System

The MicroNet Plus chassis uses two load sharing power modules to provide redundant power supply for the motherboard, CPU, and I/O modules. The power module has a dual slot width and is located in the PS1 and PS2 slots at both ends of the chassis. The system supports three power input specifications: low voltage (24 Vdc input), high voltage (110 Vac/dc input), and high voltage 220 Vac input versions.

The power module is equipped with four LED indicator lights, which respectively display information such as power status, input faults, overheating, and power faults, making it easy to diagnose quickly. The system design follows the safety requirements of Class I and Division 2 areas and requires the use of delay fuses or circuit breakers that comply with local regulations.

2.3 I/O module and on-site connection

Each I/O module is connected to the field terminal module (FTM) through a front panel connector, which is used to connect field wiring. For the communication module, there is no need for FTM, and the cable is directly connected to the front panel of the communication module.

The system provides two levels of redundancy:

Sensor level redundancy: Connect two external input devices to two independent input channels

Module level redundancy: Connect two external input devices to two independent I/O modules

Output redundancy can be achieved by adding external relays, and for actuator output, a dual coil actuator can be used to ensure continuous operation in the event of a single point fault.

3、 Detailed Explanation of Chassis Configuration

3.1 14 slot chassis

The MicroNet Plus 14 slot chassis provides redundant CPU capability and more I/O slots, while improving airflow and system reliability. The chassis adopts a modular design, with each module containing a pre formed cage, cooling fan, and high-temperature detection temperature switch. The chassis has a total of 14 CPU and I/O slots available for use.

The main features include:

New dual slot wide redundant load sharing power supply

Redundant intelligent fans can provide early notification of fan failures

The motherboard has a built-in temperature switch with a trigger point of 65 ° C ± 3 ° C

Support redundant hot swappable CPUs

3.2 8-slot chassis

The MicroNet Plus 8-slot chassis also provides redundant CPU capability and more I/O slots, adopting similar design concepts and technical features as the 14 slot chassis. The chassis has a total of 8 CPU and I/O slots available for use, and also features redundant intelligent fans and temperature monitoring functions.

4、 Analysis of CPU module technology

4.1 CPU P1020 module

The CPU P1020 module is based on an 800 MHz dual core processor, equipped with 512 MB RAM and 768 MB flash memory, and supports multiple communication peripherals, including 4 Ethernet ports (2 1000 Mbps, 2 100 Mbps), 2 real-time network ports, 1 service port, and 5 CAN ports.

This module supports both simplex and redundant operation modes, designed specifically for working environments in the industrial market from 0 ° C to+55 ° C. The module supports hot swapping, but it should be reset before removal to ensure elegant system failover.

4.2 PowerPC CPU 5200 module

The PowerPC CP5200 module uses the Motorola MPC5200 processor, equipped with 128 MB DDR RAM and 64 MB flash memory, and supports multiple communication peripherals, including 2 Ethernet ports, 2 real-time network ports, 1 serial port, 1 service port, and 2 CAN ports.

This module is designed for extreme industrial environments ranging from -40 to+85 ° C, with built-in FPGA providing VME bus master/slave functionality and other functions required for redundant systems.

5、 Communication module and network topology

5.1 Remote RTN module

The Remote Real Time Network (RTN) module is designed for rack expansion, with the main function of collecting local I/O module data and communicating with the host rack CPU, while providing redundant fault switching control for the rack. The RTN module supports simplex and redundant systems, and each RTN expansion chassis installs a remote RTN module in the first slot (CPU1).

5.2 SIO module

The SIO (Serial Input/Output) intelligent enhancement module provides four serial communication ports and interfaces with the VME bus. Module manages four serial ports: Port 1 and Port 2 are RS-232 ports; Ports 3 and 4 support RS-232, RS-422, or RS-485 communication protocols. The module has two LEDs (running and faulty) and no switch.

6、 Discrete I/O module

6.1 48/24 Discrete Combination Module

The HDDIO module provides 48 optically isolated discrete inputs and 24 discrete outputs, without calibration, and can be directly replaced with modules of the same model. This module supports two types of FTM I/O configurations:

Configuration 1: A 48/24 discrete FTM is connected to the HDDIO module via two high-density analog/discrete cables, and then connected to a 32 channel relay module or two 16 channel relay modules via low-density discrete cables.

Configuration 2: Two 24/12 discrete FTMs (DIN rail mounted) are connected to the HDDIO module via two high-density analog/discrete cables.

6.2 48 channel discrete input module

Each 48 channel discrete input module is connected to two independent FTMs through two low-density discrete cables. The module provides discrete signal inputs for 48 independent switch or relay contact points, which are optically isolated from other parts of the MicroNet control circuit.

6.3 64 channel discrete output module

The 64 channel discrete output module can independently control 64 outputs and operate according to commands from the CPU module. The module has no potentiometer and does not require calibration. It can be directly replaced with modules of the same model. This module can be connected to two 32 channel relay modules, four 16 channel relay modules, or a combination of both types.

7、 Analog I/O module

7.1 Intelligent Enhancement Module for Speed Sensor

This module provides four speed inputs, factory configured as MPU or Eddy inputs. The module has no potentiometer and does not require calibration. It can be directly replaced with modules of the same model. The speed input configuration depends on the module material number.

7.2 24/8 Simulated Intelligent Enhancement Module

This module provides 24 analog inputs and 8 4-20 mA outputs, without potentiometers or calibration, and can be directly replaced with modules of the same model. The module offers three different configurations, and all 4-20 mA analog inputs can be used with two-wire ungrounded (loop powered) transmitters or isolated (self powered) transmitters.

7.3 Speed/Analog IO Combination Intelligent Enhancement Module

This module provides four speed inputs (configurable as MPU, Prox, or Eddy inputs in GAP applications) as well as 12 analog inputs and 4 4-20 mA outputs. The analog input can be configured as 0-5VDC voltage mode or 4-20mA current mode in GAP applications.

8、 Safety regulations and compliance

The MicroNet digital control system follows strict safety standards and regulatory requirements:

8.1 European Compliance

CE mark: The product complies with the relevant EU directive requirements

RoHS: Compliant with Directive 2011/65/EU requirements

EMC Directive: Compliant with the 2014/30/EU Electromagnetic Compatibility Directive

Low Voltage Directive: Compliant with the 2014/35/EU Low Voltage Equipment Directive

ATEX Directive: Compliant with the 2014/34/EU Directive on Equipment for Potential Explosive Environments

8.2 North American Compliance

CSA certification: applicable to Class I, Division 2, Groups A, B, C, and D areas, with a maximum ambient temperature of 55 ° C

8.3 Classification Society Certification

American Bureau of Shipping (ABS): Complies with steel vessel code requirements

Lloyd's Register (LR): Complies with LR type approval test specifications

DNV/GL: Complies with standard certification requirements

9、 Installation and Maintenance Guide

9.1 Installation precautions

The MicroNet digital control system must be installed in a metal enclosure or cabinet to meet EMC directive requirements. Please refer to section 15 of manual 26166V2 for installation location and specific cabinet construction requirements.

The system grounding requirements are strict, and the grounding leakage current exceeds 3.5 mA. Before supplying power to the MicroNet control device, it is necessary to verify that the PE terminal is connected. Fixed wiring installation is required, and the main power circuit should be blown correctly according to national standards. It is recommended to use European T-type fuses.

9.2 Electrostatic discharge protection

The electronic control device contains electrostatic sensitive components, and the following precautions should be taken to prevent damage:

Release body static electricity before handling control devices

Avoid using plastic, vinyl and foam around printed circuit boards

Do not touch the components or conductors on the printed circuit board with your hands or conductive devices

9.3 Fault diagnosis and troubleshooting

The system provides comprehensive diagnostic functions, which can monitor system status, view fault codes, and configure network settings through AppManager software. Each module is equipped with LED indicator lights to display module status and fault information, making it easy to quickly locate and solve problems.

10、 Technological development trends and application prospects

With the advancement of Industry 4.0 and digital transformation, MicroNet digital control systems continue to evolve and integrate new technologies to meet more stringent industrial application requirements

10.1 Intelligent Upgrade

The new generation MicroNet control system has strengthened support for condition monitoring and predictive maintenance, helping users optimize equipment performance and reduce unexpected downtime by integrating more advanced diagnostic algorithms and data analysis functions.

10.2 Communication Protocol Extension

The system continues to expand its support for modern industrial communication protocols, including OPC UA, MQTT, and higher-level Ethernet protocols, ensuring seamless integration with factory information systems.

10.3 Network Security Enhancement

Faced with increasingly severe industrial network security challenges, Woodward continuously strengthens the security features of MicroNet control systems, including secure boot, communication encryption, and access control functions.