The IS200EROCH1A is an Exciter Regulator Options Card designed by General Electric (GE) for its EX2100™ Excitation Control System. This board is the standard version within the EROC series, primarily used in the EX2100 regulator control system (including both simplex and redundant applications) to provide support for various optional functions, including ground detector interface, keypad support, and terminal board power connection.
The IS200EROCH1A board plays a critical role in expanding optional functions within the EX2100 regulator control system. It communicates with the ERIO board via the backplane, providing the following options support:
GE Ground Detector: Supports the standard GE ground detection function.
Third-Party Ground Detector: Supports integration with third-party ground detection equipment, providing up to three inputs (Ground Alarm, Ground Detector Malfunction, Diode Fault Monitor).
Keypad Support: Communicates with the keypad via RS-232C, providing two keypad interface locations (one on the board faceplate, one on the backplane).
Terminal Board Power Connection: Provides power connections for associated terminal boards.
The IS200EROCH1A board features a compact design with dedicated functions, making it an essential component for achieving comprehensive protection and monitoring capabilities in the EX2100 regulator control system. In simplex systems, one EROC is installed in the ERBP. In redundant systems, one EROC is installed in the ERBP (M1) and another in the ERRB (M2/C).
Key features of the board include:
Multiple Options Support: Supports both GE and third-party ground detectors.
Redundant Keypad Interface: Provides two keypad connection locations to accommodate different installation requirements.
Backplane Communication: Exchanges data with the ERIO via the backplane.
Passive Design: The board has no complex adjustable hardware, ensuring high reliability.
II. Main Functions
The primary functions of the IS200EROCH1A include, but are not limited to, the following:
1. GE Ground Detector Support
The IS200EROCH1A board provides an interface for the standard GE ground detector, enabling continuous monitoring of the generator field circuit's insulation to ground. Ground detector signals are transmitted via the backplane to the ERIO and DSPX for protection logic execution by the control system.
2. Third-Party Ground Detector Interface
The board supports integration with third-party ground detection equipment, providing three independent input channels:
Ground Alarm Input: Activated by the third-party device when a ground fault is detected.
Ground Detector Malfunction Input: Activated when the ground detector itself experiences a fault.
Diode Fault Monitor Input: Monitors the status of diodes within the ground detector.
These signals are transmitted via the backplane to the control system for seamless integration with the GE system.
3. Keypad Support
The IS200EROCH1A board communicates with the local operator keypad via an RS-232C serial interface. The board provides two keypad connection locations:
Through the keypad, operators can perform functions such as start/stop commands, regulator transfer, and parameter viewing/modification.
4. Terminal Board Power Connection
The board provides power connections for associated terminal boards (e.g., EPCT, ECTB), ensuring these I/O boards function correctly. Power is sourced from the EPSM via the backplane and distributed by the EROC to the respective terminal boards.
5. Backplane Communication
The IS200EROCH1A board communicates with the ERIO board via the backplane, exchanging the following information:
6. Status Indication
The board front panel typically features LED indicators for:
Power OK
Ground detector status
Communication activity
III. System Applications
1. Application in EX2100 Regulator Control System
The IS200EROCH1A is the core board for expanding optional functions within the EX2100 Regulator Control System. Its roles within the system include:
Ground Detector Interface: Provides an interface for GE or third-party ground detectors, transmitting ground status information to the control system for insulation monitoring of the generator field circuit.
Human-Machine Interface Support: Provides local control and monitoring means for operators via the keypad interface.
Power Distribution: Provides power connections for associated terminal boards, ensuring I/O boards function correctly.
System Expansion: Offers flexible options expansion capability for the regulator control system to meet diverse user requirements.
2. Simplex System Configuration
In a simplex regulator system, one IS200EROCH1A is installed in the ERBP, working with the ERIO of the M1 controller to provide ground detection and keypad support.
3. Redundant System Configuration
In a redundant regulator system, two IS200EROCH1A boards are required:
This redundant configuration ensures that options functions continue even if one controller fails.
4. Coordination with ERIO
The IS200EROCH1A works closely with the ERIO board via the backplane:
EROC is responsible for acquiring ground detector status and keypad data.
ERIO is responsible for transferring this data via DPM to the DSPX processor.
DSPX executes protection logic and human-machine interface responses based on this data.
5. Ground Detection Function Implementation
The ground detection function implemented via the IS200EROCH1A features:
Continuous Monitoring: Real-time monitoring of the field circuit's insulation to ground.
Multi-Source Support: Supports both GE and third-party detectors simultaneously.
Fault Alarm: Generates alarm or trip signals when ground resistance falls below a threshold.
Self-Diagnosis: Monitors the ground detector's own status to ensure system reliability.
6. Typical Application Scenarios
Ground protection for synchronous generator excitation systems
Options expansion for steam turbine generator EX2100 regulator systems
Excitation regulators for hydro turbine generators
Excitation regulator systems for gas turbines
Industrial excitation systems requiring third-party ground detectors
IV. Detailed Interface Description
1. Backplane Connector
The IS200EROCH1A board connects to the ERBP or ERRB via backplane connectors, enabling the following functions:
Communication with ERIO: Exchanges data with the ERIO board via the backplane.
Power Supply: Receives operating power from the EPSM via the backplane.
Keypad Interface: The backplane provides a second keypad connector.
Refer to ERBP and ERRB related documentation for specific backplane connector pin assignments.
2. GE Ground Detector Interface
The GE ground detector connects to the EROC via the backplane, transmitting signals including:
Refer to GE ground detector documentation for specific interface definitions.
3. Third-Party Ground Detector Interface
Third-party ground detectors connect to the EROC via terminals or connectors, providing three input signals:
| Input | Signal Type | Description |
| Ground Alarm | Dry contact or level | Closes or goes high when a ground fault is detected |
| Detector Malfunction | Dry contact or level | Closes or goes high when the ground detector itself fails |
| Diode Fault | Dry contact or level | Monitors the status of diodes within the detector |
These signals are conditioned by the EROC and transmitted to the ERIO via the backplane.
4. Keypad Interface
The keypad interface uses RS-232C serial communication and provides two physical connection points:
Front Panel Connector: Standard 9-pin D-Sub or circular connector for direct keypad connection.
Backplane Connector: Located on the ERBP/ERRB for routing cables through the cabinet door to connect the keypad.
The keypad communication protocol supports:
Displaying menus and status information
Receiving operator key presses
Parameter modification and confirmation
Alarm viewing and resetting
5. Power Connection
The IS200EROCH1A receives operating power from the EPSM via the backplane and distributes power to associated terminal boards. Specific power parameters are consistent with EPSM outputs, including:
+5 V dc
±15 V dc
+24 V dc
6. Front Panel Indicators
The board front panel typically features LED indicators. A typical configuration includes:
| LED | Color | Description |
| PWR | Green | Power OK |
| GND DET | Yellow | Ground detector status (blinking indicates detection in progress, steady on indicates ground fault) |
| COMM | Green | Keypad communication activity |
Specific indicator definitions may vary by hardware revision; refer to the actual board markings.
V. Configuration and Installation
1. Configuration Method
The IS200EROCH1A board has no hardware jumpers; all configuration is done via software:
Ground Detector Type Selection: Software configurable for GE or third-party detectors.
Third-Party Input Polarity Configuration: Configurable for normally open or normally closed contacts.
Keypad Baud Rate Configuration: RS-232C communication parameters configurable.
Configuration is typically performed using the GE Control System Toolbox software.
2. Mounting Location
The IS200EROCH1A board inserts into designated slots in the EX2100 regulator control system backplane:
Simplex System: Inserts into the M1 controller slot in the ERBP (typically adjacent to the ERIO).
Redundant System: One board inserts into the M1 controller slot in the ERBP, and another inserts into the M2/C controller slot in the ERRB.
Ensure the board is inserted into the correct slot; incorrect insertion may prevent the control system from functioning properly or damage the board.
3. Installation Steps
Verify Power Off: Ensure the system is completely de-energized.
Open Cabinet Door: Open the control cabinet door.
Insert Board: Align the IS200EROCH1A board with the correct slot and push it in along the guides.
Seat Board: Using thumbs, firmly press the top and bottom of the faceplate simultaneously to initially seat the board.
Tighten Screws: Alternately tighten the top and bottom faceplate screws evenly to ensure the board is squarely seated.
Connect Cables: If using the front panel keypad interface, connect the keypad cable.
Restore Power: Close the cabinet door and restore power to the system.
4. Online Replacement
In redundant systems, the IS200EROCH1A supports online replacement:
Use diagnostic tools to confirm the section (M1 or M2/C) containing the failed board.
Turn off power to the corresponding section on the EPDM.
Verify that all power indicators on boards in that section are off.
Remove the failed board.
Install the new board.
Restore power to the section.
Verify normal operation of the new board using diagnostic tools.
