The IS200EISBH1A Exciter ISBus Board (EISB) is a dedicated communication interface board designed by General Electric (GE) for the EX2100 Excitation System. It is applicable to M1, M2, and C controllers. The primary function of this board is to facilitate communication between the controllers and field devices via fiber optics and to exchange data with the DSPX controller through the control backplane. Additionally, the EISB provides RS-232C communication interfaces for external tool ports and keypad ports, facilitating on-site commissioning and monitoring.
In redundant exciter systems, the EISB also integrates ISBus interface electronics. ISBus is a proprietary GE communication protocol used here for data transfer among the M1, M2, and C controllers, ensuring high system reliability and bumpless redundancy switching capability.
The EISB features a single-slot, 3U height modular design and is installed in the control rack beneath the DSPX controller. Its front panel is equipped with multiple fiber optic connectors for receiving voltage and current signals from the generator field (and optionally from a potential-source exciter), while also interacting with the ground detection module.
II. Key Features
Fiber Optic Communication Interface: Receives and transmits variable frequency signals via fiber optics, providing electrical isolation from high-voltage measurement boards (EDCF) to ensure system safety.
ISBus Communication Protocol: Supports high-speed data exchange between controllers in redundant exciter systems.
RS-232C Communication Interface: Provides serial communication with the keypad and an external computer (tool port), supporting baud rates from 1200 to 38.4 kbps.
No LEDs, Jumpers, or Fuses: Simplifies hardware design, reduces potential failure points; all configuration is done via software.
Front Panel Reset Switch: Recessed design prevents accidental operation.
24V DC Power Supply: Provides power for the keypad and tool port via the backplane.
Supports Online Replacement (Hot Swapping): In redundant systems, a faulty EISB board can be replaced while the exciter is running, without requiring shutdown.
III. System Integration and Application
The IS200EISBH1A is primarily used in EX2100 Excitation Control Systems, acting as a communication bridge between the controllers and field measurement devices. It works in conjunction with the DSPX controller, EDCF measurement boards, ground detection modules, etc., to form a complete excitation regulation and monitoring system.
Integration with DSPX Controller: The EISB is mounted beneath the DSPX and communicates with it via the backplane connector.
Coordination with EDCF Boards: Receives generator field voltage and current signals, as well as optional exciter voltage and current signals, via fiber optics.
Communication with Ground Detection Module: Receives and transmits ground detection signals to implement rotor ground protection functions.
Application in Redundant Systems: Shares data among M1, M2, and C controllers via the ISBus protocol, enabling bumpless transfer.
IV. Front Panel Interface Details
The front panel of the IS200EISBH1A features a clean yet powerful design, primarily including:
1. Fiber Optic Receivers (Four Units)
Generator Field dc Voltage input: Receives generator field DC voltage signal from the EDCF board.
Generator Field dc Current input: Receives generator field DC current signal from the EDCF board.
Exciter Voltage input (optional): Optionally receives exciter voltage signal from the EDCF board.
Exciter Current input (optional): Optionally receives exciter current signal from the EDCF board.
2. Fiber Optic Receiver and Transmitter (One Unit)
3. Reset Switch
V. Detailed Communication Functions
1. Fiber Optic Communication
Fiber optic transmission technology ensures electrical isolation between the EISB and high-voltage measurement boards (EDCF), enhancing system noise immunity and safety. All fiber optic connectors use standard industrial interfaces, supporting reliable transmission of high-frequency variable frequency signals.
2. ISBus Communication
ISBus is a proprietary high-speed communication protocol from GE, used for transmitting real-time data between M1, M2, and C controllers in redundant exciter systems. The protocol supports a multi-master architecture, ensuring seamless system transfer and continuous excitation regulation in the event of a single controller failure.
3. RS-232C Communication
The EISB incorporates two RS-232C driver circuits:
Keypad Port: Used to connect a local keypad for parameter setting, status monitoring, and manual control.
Tool Port: Used to connect an external computer for system diagnostics, firmware upgrades, and data acquisition via dedicated GE commissioning software.
The RS-232C interfaces support various baud rates (1200 to 38.4 kbps) to accommodate different commissioning needs.
VI. Installation and Replacement Guide
1. Handling Precautions
Static Sensitive Device Warning:
To prevent component damage caused by static electricity, treat all boards with static sensitive handling techniques. Wear a wrist-grounding strap when handling boards or components, but only after boards or components have been removed from potentially energized equipment and are at a normally grounded workstation.
Storage Requirements:
Printed wiring boards may contain static-sensitive components. Therefore, GE ships all replacement boards in antistatic bags. Use the following guidelines when handling boards:
2. Offline Replacement Procedure (For Non-Redundant Systems)
Electric Shock Hazard Warning:
To prevent electric shock, turn off power to the exciter, then test to verify that no power exists in the board before touching it or any connected circuits.
Equipment Damage Warning:
To prevent equipment damage, do not remove, insert, or adjust board connections while power is applied to the equipment.
Ensure the exciter has been de-energized: Refer to the EX2100 Installation and Startup Guide (GEH-6631) for complete de-energizing procedures and follow all local practices of lock-out/tag-out.
Open the control cabinet door: Check that the power indicators on the EPDM and EPSM power supplies are off, and the LEDs on the controller are off.
Disconnect the fiber optic cables: Disconnect all fiber optic cables from the front of the EISB board. Be sure they are labeled for correct reassembly.
Carefully remove the DSPX and EISB boards:
a. Loosen the screws at the top of the DSPX faceplate and the bottom of the EISB faceplate, near the ejector tabs. (The screws are captive in the faceplate and should not be removed.)
b. Unseat the DSPX and EISB by raising the ejector tabs.
c. Using both hands, gently pull both boards from the rack.
Separate DSPX and EISB: Remove the DSPX from the top of the EISB, and attach it to the replacement EISB board.
Insert the replacement boards: Slide the replacement DSPX and EISB boards into the correct slot in the rack.
Initial seating: Begin seating the boards by firmly pressing the top and bottom of the faceplates at the same time with your thumbs.
Final seating: Finish seating the boards in the slot by starting and then alternately tightening the screws at the top and bottom of the faceplate assembly. Tighten the screws evenly to ensure the boards are seated squarely.
Reconnect cables: Reconnect all communication cables that were disconnected.
3. Online Replacement Procedure (For Redundant Systems)
For a redundant control system, it is possible to replace the failed EISB while the exciter is running. You have the option to leave the failed EISB in place, and let the exciter run on the remaining controller(s). However, in the unlikely event of a second board failure in another section, the exciter will shut down. If you decide to change the EISB board, follow the procedure below:
Confirm the failed EISB: Open the control cabinet door and confirm the failed EISB from the indicators on the front of the controllers.
De-energize the relevant control section: De-energize the section of the control rack containing the EISB to be replaced (M1, M2, or C) by switching off the appropriate section of the exciter power distribution module (EPDM). Check that the LED indicators on the appropriate sections of the EPDM and EPSM are both off.
Confirm control transfer: Check the de-energized controller and ESEL LEDs to confirm that control is transferred to the other master. Check that all power indicators on the boards in the relevant section are off before touching the EISB or any connected circuits.
Disconnect the fiber optic cables: Disconnect up to six fiber optic communication cables from the EISB front panel. Be sure they are labeled.
Carefully remove the DSPX and EISB boards:
a. Loosen the screws at the top of the DSPX faceplate and the bottom of the EISB faceplate, near the ejector tabs.
b. Unseat the DSPX and attached EISB by raising the ejector tabs.
c. Using both hands, gently pull both from the rack.
Separate DSPX and EISB: Remove the DSPX from the top of the EISB, and attach it to the replacement EISB.
Insert the replacement boards: Slide the replacement EISB board and attached DSPX board into the correct slot in the rack.
Initial seating: Begin seating the board by firmly pressing the top and bottom of the faceplates at the same time with your thumbs.
Final seating: Finish seating the module in the slot by starting and then alternately tightening the screws at the top and bottom of the faceplate assembly. Tighten the screws evenly to ensure the module is seated squarely.
Reconnect cables: Reconnect all communication cables that were disconnected.
Restore power: Apply power to the appropriate section of the control rack from the EPDM, and check that the LED power indicators on the EPDM and EPSM come on. Check that the green power LEDs on the adjacent controller boards come on.
VII. Diagnostics and Status Monitoring
Although the IS200EISBH1A itself has no LED indicators, its operational status and fault information can be obtained through the following methods:
Via the DSPX Controller: The EISB communicates with the DSPX via the backplane; all diagnostic data (including fiber optic signal quality, communication status, power status, etc.) can be read through the DSPX's monitoring software.
Via the Tool Port: Connect an external computer and use GE's dedicated commissioning software to view the EISB's operating parameters and fault logs in real-time.
System Alarms: When the EISB detects communication failures or signal anomalies, it sends alarm information to the control system via ISBus or RS-232C, which can be viewed by the operator on the Human-Machine Interface (HMI).
VIII. Typical Applications
EX2100 Excitation System: Serves as the communication interface for M1, M2, and C controllers, enabling data exchange with EDCF measurement boards and ground detection modules.
Redundant Excitation Systems: In dual or triple modular redundant (TMR) configurations, facilitates data synchronization and failover between controllers via the ISBus protocol.
Power Plant Excitation Regulation: Used in excitation regulation systems for steam turbine generators, hydroelectric generators, and gas turbine generators.
Industrial Synchronous Motor Excitation: Suitable for excitation control of large industrial synchronous motors.
Excitation System Commissioning and Maintenance: Connects to a laptop via the tool port for on-site commissioning, parameter tuning, and fault diagnosis.
