The GE IS200EDCFG1AED Exciter DC Feedback Board is a specialized measurement and isolation module used within the EX2100™ Excitation Control system. As a member of the EDCF board family, the IS200EDCFG1AED Exciter DC Feedback Board measures field current and field voltage at the SCR bridge, converts these analog quantities into frequency-encoded signals, and interfaces to the EISB board in the control panel over a high-speed fiber-optic link. The fiber-optic transmission provides galvanic voltage isolation between the high-voltage SCR bridge and the low-voltage control electronics, and it delivers high noise immunity in the electrically hostile environment of the excitation power stage.
The IS200EDCFG1AED Exciter DC Feedback Board is identified by the GE part numbering convention used throughout the Industrial Control Systems product line. The "IS200" prefix identifies the board as a GE Industrial Control Systems product, with "200" specifically indicating that the board is a base-level assembly. The "EDCF" acronym identifies the board's functional designation as an Exciter DC Feedback board. The "G1" designation identifies the hardware group and normal coating, while the "AED" suffix identifies the artwork and functional revision combination. All digits are important when ordering or replacing any board, as boards of different revision levels may not contain identical hardware, and GE ensures backward compatibility of replacement boards while noting that different revision levels may not contain identical components.
The IS200EDCFG1AED Exciter DC Feedback Board is designed for direct connection to the field circuit of the excitation system. The field voltage is measured across the negative terminal of the bridge and the positive terminal of the current shunt, while the field current is measured across a DC shunt at the SCR bridge. The board provides seven selector settings to scale down the bridge voltage depending on the type of bridge application, and it uses a voltage-controlled oscillator to convert the scaled analog signals into frequency pulses for fiber-optic transmission. Two fibers are used, one for each signal, and two types of fiber cable are supported: plastic optical fiber for distances up to 10 meters, and hard-clad silica fiber for distances up to 90 meters. The minimum bending radius of these cables is 1.5 inches.
This product introduction provides detailed technical information, functional descriptions, connector assignments, jumper configuration guidance, and comprehensive specifications for the GE IS200EDCFG1AED Exciter DC Feedback Board, serving as an essential reference for excitation control engineers, maintenance technicians, and system integrators working with GE industrial control equipment.
Functional Architecture and Signal Processing
The IS200EDCFG1AED Exciter DC Feedback Board is built around a robust architecture for field voltage measurement, field current measurement, signal scaling, voltage-to-frequency conversion, and fiber-optic transmission. The board performs several distinct functions that together ensure accurate and safe acquisition of the field quantities required by the excitation control system.
The field voltage feedback circuit on the IS200EDCFG1AED Exciter DC Feedback Board provides seven selector settings to scale down the bridge voltage, depending on the type of bridge application. The field voltage is measured across the negative terminal of the bridge and the positive terminal of the current shunt. After scaling the voltage with the jumped resistors, the signals are input into a differential amplifier, which controls the voltage-controlled oscillator. The selectable voltage settings cover a range of PPT bridge voltages from 140 V RMS to 1300 V RMS, with the 999 V RMS and 1300 V RMS settings available on later board revisions. Revision IS200EDCFG1BAA and later boards are rated for up to 1400 V RMS PPT. Only one voltage setting jumper is inserted at any time, ensuring that the scaling is unambiguous and correctly matched to the application.
The field current feedback circuit on the IS200EDCFG1AED Exciter DC Feedback Board measures the field current across a DC shunt at the SCR bridge. This generates a low-level signal with a maximum value of 500 mV, which is input to a differential amplifier. The output voltage from the amplifier ranges from −5 V to +5 V into a voltage-controlled oscillator. The VCO converts this analog voltage into a frequency signal that is transmitted over the fiber-optic link, providing accurate and noise-immune measurement of the field current.
The power supply section of the IS200EDCFG1AED Exciter DC Feedback Board receives power from an external ±24 V DC source through connector J16. From this input, three voltage regulators produce +15 V DC, −15 V DC, and +5 V DC. The PSOK green LED is driven by the ±15 V DC output voltages, providing a visual indication that the power supply is operating correctly. The board has one green LED indicating the power supply is operating (PSOK), which allows maintenance personnel to quickly verify that the board is receiving power and that the internal regulators are functioning.
Field Voltage Feedback
The field voltage feedback function of the IS200EDCFG1AED Exciter DC Feedback Board is critical for the excitation control system because it provides the measurement of the generator field voltage that is used in the voltage regulation and protection algorithms. The field voltage is measured across the negative terminal of the bridge and the positive terminal of the current shunt, which provides a direct measurement of the voltage applied to the field winding.
The scaling of the field voltage is accomplished through a set of jumpers that select the appropriate voltage divider ratio for the application. The jumpers JP1 through JP6, JP9, and JP10 provide settings for PPT bridge voltages of 140 V RMS, 253 V RMS, 400 V RMS, 506 V RMS, 633 V RMS, 739 V RMS, 999 V RMS, and 1300 V RMS respectively. Only one of these jumpers is inserted at any time, and the selection must match the actual PPT voltage of the SCR bridge in the application. An incorrect jumper setting would result in an incorrect scaling of the field voltage feedback, which could cause the control system to misoperate.
After scaling, the field voltage signal is input into a differential amplifier that provides buffering and common-mode rejection. The output of the differential amplifier controls the voltage-controlled oscillator, which converts the analog voltage into a frequency signal. This frequency signal is then transmitted over the fiber-optic link to the EISB board, where it is decoded and used by the control system.
Field Current Feedback
The field current feedback function of the IS200EDCFG1AED Exciter DC Feedback Board is equally critical because it provides the measurement of the generator field current that is used in the current regulation, limiting, and protection algorithms. The field current is measured across a DC shunt at the SCR bridge, which generates a low-level voltage signal proportional to the field current.
The maximum value of the shunt signal is 500 mV, which is input to a differential amplifier. The differential amplifier provides gain and buffering, producing an output voltage that ranges from −5 V to +5 V. This output voltage is then input to the voltage-controlled oscillator, which converts the analog voltage into a frequency signal for fiber-optic transmission. The use of a VCO for the current feedback provides excellent linearity and noise immunity, ensuring that the field current measurement is accurate even in the presence of the switching noise generated by the SCR bridge.
The field current signal is transmitted over a separate fiber from the field voltage signal, ensuring that the two measurements are independent and that a fault in one channel does not affect the other. The fiber-optic connectors CF OF and VF OF are used for the current feedback and voltage feedback respectively, and both use the HFBR-1528 fiber-optic driver/connector.
Power Supply
The power supply architecture of the IS200EDCFG1AED Exciter DC Feedback Board is designed to provide clean, regulated power to the measurement and transmission circuits. Power is supplied to the board from an external ±24 V DC source through connector J16. The +24 V DC input is provided on pin 1, and the 24 V DC common input is provided on pin 2. From this input, three voltage regulators produce the +15 V DC, −15 V DC, and +5 V DC required by the board's circuits.
The ±15 V DC outputs are used by the operational amplifiers and the voltage-controlled oscillators, while the +5 V DC output is used by the fiber-optic drivers and the logic circuits. The PSOK green LED is driven by the ±15 V DC output voltages, so it illuminates when both the positive and negative 15 V supplies are within regulation. If either supply fails, the PSOK LED will extinguish, providing a clear visual indication of a power supply fault.
Connector Assignments and Interfaces
The IS200EDCFG1AED Exciter DC Feedback Board provides a comprehensive set of connectors that interface with the external power source, the field current shunt, the field voltage measurement point, and the fiber-optic communication link to the EISB board. Each connector serves a specific function in the overall signal chain, and understanding these connector assignments is essential for installation, maintenance, and troubleshooting.
The J16 connector brings the ±24 V DC power into the board. Pin 1 provides the external power +24 V DC input to the DC-DC converter, and pin 2 provides the external power 24 V DC common input to the DC-DC converter. This connector must be wired to a suitable external power source that is capable of supplying the board's power requirements.
The P1 connector brings in the voltage across the field current shunt resistance. Pin 1 provides the field current and voltage shunt feedback positive connection, which is also the entry side of the DC shunt and the SCR bridge positive. Pin 2 provides the field current shunt feedback return connection, which is the field positive. This connector must be wired to the shunt with the correct polarity to ensure accurate current measurement.
The E1 connector provides the field voltage feedback negative connection, which is the SCR bridge negative. This is a stab-on connection that must be securely attached to the field voltage measurement point. The field voltage is measured between the E1 connection and the P1 pin 1 connection, so both connections must be properly made for accurate voltage measurement.
The fiber-optic connectors CF OF and VF OF provide the communication link to the EISB board. CF OF transmits the field current feedback pulses, and VF OF transmits the field voltage feedback pulses. Both connectors use the HFBR-1528 fiber-optic driver/connector, and the type of fiber cable used must match the jumper settings of JP7 and JP8.
Jumper Configuration
The IS200EDCFG1AED Exciter DC Feedback Board includes a set of jumpers that must be configured for the specific application. The voltage scaling jumpers JP1 through JP6, JP9, and JP10 select the PPT bridge voltage range, and only one of these jumpers is inserted at any time. The fiber-optic cable type jumpers JP7 and JP8 select the type of fiber cable used for the current feedback and voltage feedback outputs respectively, and these two jumpers are set independently.
The voltage scaling jumper descriptions are as follows: JP1 is inserted for a PPT voltage of 140 V RMS, JP2 for 253 V RMS, JP3 for 400 V RMS, JP4 for 506 V RMS, JP5 for 633 V RMS, JP6 for 739 V RMS, JP9 for 999 V RMS, and JP10 for 1300 V RMS. Revision IS200EDCFG1BAA and later boards are rated for up to 1400 V RMS PPT. The correct jumper must be selected based on the actual PPT voltage of the SCR bridge in the application, and the jumper must be verified against the system documentation before the board is placed in service.
The fiber-optic cable type jumpers JP7 and JP8 select between plastic optical fiber (POF) for distances up to 10 meters and hard-clad silica (HCS) fiber for distances up to 90 meters. JP7 configures the current feedback output, and JP8 configures the voltage feedback output. Both jumpers must be set to match the actual fiber cable type used in the installation, and the fiber cable must be selected with the appropriate bending radius of 1.5 inches minimum.
Application Suitability and System Integration
The IS200EDCFG1AED Exciter DC Feedback Board is an integral component of the EX2100™ Excitation Control system, providing the field voltage and field current measurements that are essential for the voltage regulation, current regulation, limiting, and protection functions of the excitation system. Its fiber-optic transmission link provides galvanic isolation between the high-voltage SCR bridge and the low-voltage control electronics, ensuring safe and reliable operation in the demanding environment of the excitation power stage.
In the EX2100 Excitation Control, the IS200EDCFG1AED Exciter DC Feedback Board is typically installed in a redundant configuration, with three boards providing the field voltage and field current measurements for the three control channels. If three redundant EDCF boards are installed, the exciter can continue running with one board failed, providing high availability for the excitation system. However, because of the high voltages present in the field circuit, it is not possible to replace a failed EDCF board online; replacement requires that the exciter be de-energized and the field circuit be isolated.
The board's seven voltage scaling settings support a wide range of bridge applications, from 140 V RMS PPT to 1300 V RMS PPT, with later revisions rated for up to 1400 V RMS PPT. This flexibility allows the same board design to be used across a broad range of generator sizes and excitation system configurations, simplifying the spare parts inventory and reducing the engineering effort required for each application.
The IS200EDCFG1AED Exciter DC Feedback Board is designed for easy installation and maintenance. Its push lock pins allow the board to be quickly installed in and removed from the top and bottom slides of the auxiliary cabinet, and its clearly labeled connectors and jumpers simplify wiring and configuration. The PSOK green LED provides a clear visual indication of the power supply status, allowing maintenance personnel to quickly verify that the board is receiving power and that the internal regulators are functioning.
Maintenance and Lifecycle
The IS200EDCFG1AED Exciter DC Feedback Board is designed for long service life with minimal maintenance. The board contains no moving parts or user-adjustable components other than the configuration jumpers, and its solid-state construction ensures high reliability in continuous industrial operation. Routine maintenance consists of periodic visual inspection of the board, connectors, and fiber-optic cables, verification of the PSOK LED indication, and confirmation that the jumpers are set correctly for the application.
If a board fails, replacement requires careful attention to safety procedures. After turning off power to the exciter and verifying that no power exists on the board, all cables must be labeled with the correct connector name to simplify reconnection. The stab-on connector at E1 must be gently pulled loose, and connectors P1 and J16 and the fiber-optic connectors CF OF and VF OF must be disconnected. The push lock pins that hold the board in the top and bottom slides must be unlocked, and the board must be removed. The jumpers JP1 through JP9 on the new board must be checked to ensure that they are in the same position as on the original board, and the new board must be oriented in the same position as the one removed, installed in the slides, and locked in place. All cables must be reconnected as labeled and properly seated at both ends, and the auxiliary cabinet door must be closed.
GE Industrial Control Systems ensures compatibility of its replacement boards, even though boards of different revision levels may not contain identical hardware. When ordering a replacement IS200EDCFG1AED Exciter DC Feedback Board, provide the complete part number and description, the serial number, and the Material List (ML) number. The factory may substitute later versions based on availability and design enhancements, but backward compatibility of replacement boards is guaranteed.
Conclusion
The GE IS200EDCFG1AED Exciter DC Feedback Board is a reliable, robust, and highly integrated measurement and isolation module for the EX2100™ Excitation Control system. Its field voltage and field current measurement circuits, seven selectable voltage scaling settings, voltage-controlled oscillator signal conversion, and fiber-optic transmission link provide accurate and safe acquisition of the field quantities required by the excitation control system. The board's galvanic isolation, high noise immunity, and redundant configuration capability ensure reliable operation in the demanding environment of the excitation power stage.
With its clearly labeled connectors, configurable jumpers, PSOK indicator, and comprehensive documentation, the IS200EDCFG1AED Exciter DC Feedback Board is an essential component in EX2100 Excitation Control installations worldwide. Backed by GE's quality manufacturing, global support network, and commitment to backward compatibility, the IS200EDCFG1AED Exciter DC Feedback Board continues to deliver the performance, durability, and ease of use that industrial users expect from GE. Whether used in a new installation or as a replacement for an existing board, the IS200EDCFG1AED Exciter DC Feedback Board provides the field voltage and field current measurement functionality required for reliable and efficient excitation control operation.
