The IS200VCMIH2B is a VME Bus Master Controller Board designed by General Electric (GE) for its Mark VI™ Gas Turbine/Steam Turbine Control System. This board is an important hardware revision within the VCMI series, serving as the communication hub of the control system. It is responsible for data exchange between the controller and I/O boards, as well as the communication interface for the system control network, known as IONet.
The IS200VCMIH2B board plays a central role in the Mark VI control system. It is not only the VME bus master in the control and I/O racks but also manages the IDs for all the boards in the rack and their associated terminal boards. Through the IONet network, the VCMI enables high-speed data communication with multiple local or remote I/O racks, building a flexible and scalable control system architecture.
Key features of the IS200VCMIH2B include:
Two Versions Available: Offered in single network port and triple network port versions to suit different system configuration requirements.
IONet Communication: Supports the high-speed control network IONet, enabling real-time data exchange between the controller and I/O.
VME Bus Master: Acts as the VME bus master controller, managing communication for all boards within the rack.
ID Management: Automatically identifies and manages the ID information of all boards and their associated terminal boards in the rack.
Redundancy Support: Supports both simplex and triple modular redundant (TMR) system configurations.
Remote I/O: Supports connecting multiple remote I/O racks via IONet to expand system scale.
Comprehensive Diagnostics: Provides extensive board self-diagnostics and system-level diagnostic functions for easy troubleshooting.
According to the diagrams in the document, the VCMI has two versions:
Single Network Port Version: Suitable for simplex systems or as a single channel in TMR systems.
Triple Network Port Version: Suitable for TMR systems, with three ports corresponding to the R, S, and T control channels respectively.
The board design meets industrial-grade standards and is suitable for control applications in critical equipment such as gas turbines and steam turbines in power plants.
II. Main Functions
The primary functions of the IS200VCMIH2B include, but are not limited to, the following:
1. Controller and I/O Communication Interface
The IS200VCMIH2B acts as a communication bridge between the controller and I/O boards, responsible for transmitting process data, status information, and control commands between them. It exchanges data with various I/O boards (such as VAIC, VCMI, etc.) in the rack via the VME bus, while simultaneously communicating with the controller at high speed over the IONet network.
2. IONet Network Communication
IONet is the dedicated high-speed control network for the GE Mark VI control system. The IS200VCMIH2B uses IONet to achieve:
Real-time data exchange with the main controller.
Communication with multiple remote I/O racks.
Data synchronization between the three control channels (R, S, T) in TMR systems.
Transmission of system configuration and diagnostic data.
3. VME Bus Master
As the master controller of the VME bus, the VCMIH2B is responsible for:
Managing VME bus access for all I/O boards in the rack.
Arbitrating bus requests from various boards.
Executing VME bus data transfers.
Detecting and handling VME bus errors.
4. Board ID Management
The IS200VCMIH2B automatically identifies and manages the ID information of all boards and their terminal boards in the rack:
Reads the ID chip on each board to obtain information such as board type, revision, and serial number.
Compares this information with the expected values in the configuration file to ensure hardware compatibility.
Detects ID mismatches or read failures and generates corresponding fault alarms.
5. System Configuration Support
The IS200VCMIH2B supports various system configuration methods:
Simplex Systems: A single control rack, which can connect to local I/O or remote I/O racks via IONet.
TMR Systems: Three independent control channels (R, S, T), each with its own IONet, capable of connecting to local or remote I/O racks.
Mixed Configurations: Local and remote I/O can be flexibly combined based on actual requirements.
6. Power Supply Monitoring
The IS200VCMIH2B board monitors various power supply voltages within the VME rack, including:
P5 (+5 V dc)
P15 (+15 V dc)
N15 (-15 V dc)
P12 (+12 V dc)
N12 (-12 V dc)
P28A, P28B, P28C, P28D, P28E (multiple +28 V dc rails)
N28 (-28 V dc)
125 V bus voltage and its voltage to ground
When any voltage falls outside the specified operating limits, the board generates a corresponding fault alarm.
7. Diagnostics and Self-Test
The IS200VCMIH2B features comprehensive diagnostic functions, including:
Power-On Self-Test (POST)
Periodic runtime self-tests
VME bus error detection
IONet communication status monitoring
Board ID consistency checks
Power supply voltage monitoring
Controller communication status monitoring
Diagnostic results are provided via front panel LEDs and system software (Toolbox).
III. System Applications
1. Application in Mark VI Control System
The IS200VCMIH2B is the core board for controller-to-I/O communication within the Mark VI control system. Its roles within the system include:
Communication Hub: Serves as the data exchange center between the controller and I/O boards, ensuring real-time transmission of process data and control commands.
Network Interface: Connects the controller and remote I/O racks via IONet, building a distributed control system.
Bus Master: As the master controller of the VME bus, manages communication for all I/O boards in the rack.
System Management: Manages board IDs, monitors power supply status, and performs diagnostic tasks to ensure healthy system operation.
2. Simplex System Configuration
In simplex systems, the IS200VCMIH2B offers flexible configuration options:
Local I/O Configuration: All I/O boards are installed in the control rack. The VCMI communicates directly with the I/O via the VME bus.
Remote I/O Configuration: Connects one or more remote I/O racks via IONet. Each remote rack also has its own VCMI board.
Mixed Configuration: Uses both local and remote I/O simultaneously to expand system I/O capacity.
3. TMR System Configuration
In triple modular redundant systems, the triple network port version of the IS200VCMIH2B plays a key role:
Small-Scale TMR System: All I/O is mounted in the control rack. Each channel (R, S, T) has its own IONet. The VCMI's three ports connect to the three channels respectively.
Large-Scale TMR System: Each IONet supports multiple remote I/O racks. The I/O configurations for the three channels are identical (same board types and points), achieving triple redundancy.
4. Remote I/O Expansion
Via IONet, the IS200VCMIH2B can connect to multiple remote I/O racks, each potentially located far from the control rack. The advantages of this architecture include:
Reduced Field Wiring: Only one fiber optic or twisted pair cable is needed to connect the remote rack.
Strong Noise Immunity: Fiber optic communication is immune to electromagnetic interference.
Flexible Expansion: Remote racks can be added as needed to expand I/O capacity.
5. Typical Application Scenarios
Gas Turbine Control: Acts as the communication core of the control system, connecting various I/O boards to acquire and control parameters such as speed, temperature, and pressure.
Steam Turbine Control: Manages I/O signals for governor valve control, steam pressure/temperature monitoring, etc.
Generator Excitation Control: Works with the EX2100 excitation system to achieve excitation control.
Remote I/O Stations: In large power plants, collects dispersed field signals via remote I/O racks.
IV. Detailed Interface Description
1. Front Panel Interface
The IS200VCMIH2B front panel typically features:
IONet Ports: Single or triple port versions for IONet network connection.
LED Indicators: Indicate power status, operation status, network status, and fault status.
Reset Button: For manually resetting the board.
2. Backplane Connectors
The board connects to other boards in the rack via VME backplane connectors, including:
3. Terminal Board Interfaces
The IS200VCMIH2B connects to multiple terminal boards via cables, including:
J3, J4, J5, J6: Standard I/O terminal board connectors.
J3A, J4A: Additional I/O terminal board connectors.
Each connector is equipped with an ID chip storing the terminal board's type, revision, and serial number information.
4. Analog Input Monitoring
The IS200VCMIH2B monitors the following analog input signals (via backplane connector P3):
| Signal Name | Description | Connection Points |
| N125_Grd | N125 with respect to ground | P3 – 26 to 27 |
| Spare01 | Analog spare 01 | P3 – 07 to 08 |
| Spare02 | Analog spare 02 | P3 – 05 to 06 |
5. Front Panel LED Indicators
| LED | Color | Normal State | Abnormal State |
| POWER | Green | Steady On | Off indicates power failure |
| RUN | Green | Flashing | Off or steady on indicates board not running |
| IONET1 | Green/Yellow | Flashing (communication activity) | Off indicates no communication |
| IONET2 (Triple-port version) | Green/Yellow | Flashing (communication activity) | Off indicates no communication |
| IONET3 (Triple-port version) | Green/Yellow | Flashing (communication activity) | Off indicates no communication |
| FAULT | Red | Off | Steady on indicates board fault |
V. Diagnostics and Maintenance
1. Fault Code List
The IS200VCMIH2B can generate various fault codes viewable via Toolbox software. Key fault codes and descriptions are as follows:
| Fault Code | Description | Possible Cause |
| 1 | SOE Overrun | IONet communication problem |
| 2 | Flash Memory CRC Failure | Firmware programming error (board will not go online) |
| 3 | CRC Failure Override is Active | Firmware error but board allowed online |
| 4 | Watchdog circuitry is not armed | Firmware programming error (board allowed online) |
| 16 | System Limit Checking is Disabled | System checking disabled by configuration |
| 17 | Board ID Failure | Failed ID chip on VME I/O board |
| 18 | J3 ID Failure | J3 cable or terminal board ID chip problem |
| 19 | J4 ID Failure | J4 cable or terminal board ID chip problem |
| 20 | J5 ID Failure | J5 cable or terminal board ID chip problem |
| 21 | J6 ID Failure | J6 cable or terminal board ID chip problem |
| 22 | J3A ID Failure | J3A cable or terminal board ID chip problem |
| 23 | J4A ID Failure | J4A cable or terminal board ID chip problem |
| 24 | Firmware/Hardware Incompatibility | Connected terminal board type not supported |
| 25 | Board inputs disagree with the voted value | Input signal problem (sensor, wiring, board, or cable) |
| 30 | ConfigCompatCode mismatch; Firmware: #, Tre: # | tre file incompatible with firmware |
| 31 | IOCompatCode mismatch; Firmware: #; Tre: # | tre file incompatible with firmware |
| 32 | P5 voltage outside limits | VME backplane or power supply problem |
| 33 | P15 voltage outside limits | If "Remote Control", disable diagnostic; otherwise backplane or power supply problem |
| 34 | N15 voltage outside limits | If "Remote Control", disable diagnostic; otherwise backplane or power supply problem |
| 35 | P12 voltage outside limits | If "Remote I/O", disable diagnostic; otherwise backplane or power supply problem |
| 36 | N12 voltage outside limits | If "Remote I/O", disable diagnostic; otherwise backplane or power supply problem |
| 37 | P28A voltage outside limits | If "Remote Control", disable diagnostic; otherwise backplane or power supply problem |
| 38 | P28B voltage outside limits | If "Remote Control", disable diagnostic; otherwise backplane or power supply problem |
| 39-42 | P28C-E/N28 voltage outside limits | If "Remote Control", disable diagnostic; otherwise backplane or power supply problem |
| 43 | 125V Bus voltage outside limits | Source voltage or cabling problem |
| 44 | 125V Bus Ground voltage outside limits | Leakage or ground fault on 125V bus |
| 45-47 | IONet-1/2/3 Communication Failure | Loose cable, rack power, or VCMI problem |
| 48 | VME Bus Error Detected | Accumulated VME bus errors |
| 49-51 | Using Default Input Data, Rack R/S/T | IONet communication failure |
| 52 | Missed Time Match Interrupt | Possible VCMI hardware failure |
| 53 | VCMI Scheduler Task Overrun | Possibly too many I/O |
| 54 | Auto Slot ID Failure | I/O board or backplane problem |
| 55 | Card ID/Auto Slot ID Mismatch | Board ID chip failed |
| 56 | Topology File/Board ID Mismatch | ID chip mismatch with configuration |
| 57 | Controller Sequencing Overrun | Too much application code in controller |
| 58 | Controller PCODE Version Mismatch | Different software versions in three controllers |
| 59 | IONet Communications Failure (slave VCMI) | Communication problem with slave VCMI |
| 60 | VME Error Bit # | VME backplane errors |
| 61 | Controller Board is Offline | Controller failed or powered down |
| 68- | I/O Board in Slot # is Offline | I/O board failed or removed |
2. Maintenance Recommendations
Periodic Inspection: Check the fault log via Toolbox software to identify and address anomalies promptly.
Power Monitoring: Pay attention to power supply voltage alarms and troubleshoot power issues promptly.
Communication Check: Regularly check IONet communication status to ensure reliable network connectivity.
Spare Parts Management: Maintain a spare IS200VCMIH2B board to reduce downtime in case of failure.
Firmware Upgrades: Ensure firmware versions match configuration files during system upgrades.
VI. Configuration and Compatibility
1. Configuration Method
Configuration of the IS200VCMIH2B is performed via Toolbox software and mainly includes:
System Topology Configuration: Defines the number and type of control racks and remote I/O racks.
I/O Board Configuration: Specifies the type and parameters of I/O boards in each slot.
Network Configuration: Sets IONet communication parameters.
Diagnostic Configuration: Enables/disables specific diagnostic items and sets alarm thresholds.
2. Configuration File Compatibility
Configuration information is stored in a tre file. During startup, the IS200VCMIH2B compares:
ConfigCompatCode: The configuration compatibility code expected by the firmware versus the value in the tre file.
IOCompatCode: The I/O compatibility code expected by the firmware versus the value in the tre file.
If a mismatch is detected (fault codes 30-31), the tre file is incompatible with the firmware version; one of them needs to be updated.
3. Board ID Compatibility
The IS200VCMIH2B reads the ID chips on each connector and compares them with expected values. If a mismatch is detected (fault codes 17-23), it indicates that the connected terminal board type or revision does not match the configuration, or the ID chip is damaged.
4. Power Monitoring Configuration
For remote control or remote I/O applications, some power supply voltage monitoring may not be applicable. These diagnostic items can be disabled via Toolbox software to avoid false alarms.
