The IS200TRPGH1B is a Gas Turbine Primary Trip Terminal Board designed by General Electric (GE) for its Mark™ VI and Mark VIe gas turbine control systems. This board is the version within the TRPG series specifically dedicated to Triple Modular Redundant (TMR) applications. Its primary function is to receive trip commands from the primary turbine protection controller (VTUR or PTUR) and drive three Emergency Trip Solenoids (ETDs) via internal relay logic, implementing emergency shutdown protection for the gas turbine. The IS200TRPGH1B works in conjunction with the TREG board to form the primary and emergency sides of the ETD interface.
The core feature of the IS200TRPGH1B board is its nine magnetic holding relays, with three relays forming a 2-out-of-3 voting circuit for each ETD. This redundant design ensures that even if a single relay fails, it will not cause a false trip or a failure to trip, significantly enhancing system safety and reliability. The board also supports input signals from up to eight Geiger-Mueller flame detectors for gas turbine flame monitoring.
The IS200TRPGH1B is an upgraded version of the H1A, supporting 28 V control power and featuring improved contact output capability. According to the version comparison table in the document, the IS200TRPGH1B has the following characteristics:
Supports TMR applications
Output contacts support 125 V dc, 1 A and 24 V dc, 3 A
Uses 28 V control power
Suitable for standard applications
The board features a simple and reliable design with no adjustable jumpers or hardware settings; all configuration is done via controller software. Connectors JR1, JS1, and JT1 are equipped with ID chips storing the board's serial number, type, revision number, and slot location information, which is read by the I/O board for verification, ensuring hardware compatibility.
II. Main Functions
The primary functions of the IS200TRPGH1B include, but are not limited to, the following:
1. Primary Trip Protection
The IS200TRPGH1B board receives trip commands from the VTUR or PTUR controller and drives three Emergency Trip Solenoids (ETDs) through internal relay logic circuits. Each ETD is controlled by a 2-out-of-3 voting circuit composed of three relays, ensuring correct execution of trip commands even if a single relay fails.
2. 2-out-of-3 Voting Circuit
In TMR applications, trip signals from the three controllers are voted using hardware relay ladder logic within the IS200TRPGH1B. The corresponding ETD is triggered only when at least two controllers issue a trip command. This design prevents false trips caused by a single point of failure.
3. Relay Status Monitoring
The I/O board monitors the current on the relay driver control line to determine the energized or de-energized state of each relay. Additionally, one normally closed contact from each relay on the IS200TRPGH1B is monitored by the diagnostic circuitry to verify correct relay operation. Supply voltages are also monitored for diagnostic purposes.
4. Flame Detector Interface
The IS200TRPGH1B board supports signal inputs from up to eight Geiger-Mueller flame detectors. When no flame is present, the detector charges up to the supply voltage. The presence of flame causes the detector to discharge, and the discharged energy is converted into voltage pulses by the IS200TRPGH1B. The pulse frequency increases with flame intensity, ranging from 0 to 1000 pulses per second. These voltage pulses are fanned out to all three controller modules. Voltage pulses above 2.5 volts generate a logic high, and the pulse rate over a 40 ms time window is measured by a counter.
5. Coordination with TREG
The IS200TRPGH1B works in conjunction with the TREG board, which is controlled by the emergency overspeed system. The TRPG/TREG combination can drive three ETDs, with the IS200TRPGH1B handling the primary protection side and the TREG handling the emergency protection side. Each ETD circuit includes a Metal Oxide Varistor (MOV) and a current limiting resistor for current suppression.
6. Hardware ID Identification
Connectors JR1, JS1, and JT1 on the board are equipped with read-only ID chips storing the board's serial number, type, revision number, and slot location. The I/O board reads this information during initialization. If a mismatch is encountered, a hardware incompatibility fault is generated.
III. System Applications
1. Application in Mark VI Systems
In Mark VI systems, the IS200TRPGH1B works with the VTUR board. The VTUR board is located in the VME rack and connects to the IS200TRPGH1B via cables with molded plugs. VTUR provides the primary trip protection function, controlling the relays on IS200TRPGH1B to trip the main protection solenoids.
2. Application in Mark VIe Systems
In Mark VIe systems, the IS200TRPGH1B is controlled by PTUR I/O packs mounted on the TURHIC board. The I/O packs plug into the D-type connectors on TURHIC, which is cabled to IS200TRPGH1B. PTUR provides the primary trip protection function.
3. Trip Protection Operating Principle
In TMR applications, trip signals from the three controllers (R, S, T) are voted using hardware relay ladder logic within the IS200TRPGH1B. The corresponding ETD is triggered only when at least two controllers issue a trip command. This design ensures:
Prevention of False Trips: A single controller failure or spurious command will not cause a trip.
Prevention of Failure to Trip: A single relay failure will not prevent the execution of a valid trip command.
High Reliability: The system can tolerate a single point of failure while maintaining complete protection functionality.
4. Coordination with TREG
The IS200TRPGH1B and TREG board together form a complete ETD drive interface:
IS200TRPGH1B: Handles the primary protection side, controlled by the primary turbine protection controller.
TREG: Handles the emergency protection side, controlled by the emergency overspeed system.
ETD Circuit: Each ETD is controlled by both IS200TRPGH1B and TREG; a trip command from either side can trigger a shutdown.
5. Flame Monitoring Application
The IS200TRPGH1B can receive signals from up to eight Geiger-Mueller flame detectors for gas turbine flame monitoring:
Detector signals are converted to voltage pulses by the IS200TRPGH1B.
Pulse frequency is proportional to flame intensity.
Pulse signals are distributed to all three controllers.
Controllers determine flame status by counting pulses within a 40 ms window.
IV. Interface and Operating Principle
1. Relay Control and Status Monitoring
Each relay on the IS200TRPGH1B is controlled by the controller via the I/O board. The control principle is as follows:
Drive Monitoring: The I/O board monitors the current on the relay driver control line to determine the relay's energized or de-energized state.
Contact Feedback: Each relay provides a normally closed contact monitored by diagnostic circuitry to verify correct relay operation.
Power Monitoring: The relay supply voltage is monitored for diagnostic purposes.
2. 2-out-of-3 Voting Circuit
Each ETD is controlled by three relays (controlled by the R, S, and T controllers respectively) forming a 2-out-of-3 voting circuit:
The contacts of the three relays are connected in a specific configuration to form hardware voting logic.
The ETD circuit conducts only when at least two relays are energized.
This hardware voting method requires no software intervention, offers fast response times, and provides high reliability.
3. Flame Detector Interface
Operating principle of Geiger-Mueller flame detectors:
No Flame: The detector charges up to the 335 V supply voltage.
Flame Present: The detector discharges, and the discharged energy is converted into voltage pulses by the TRPGH1B.
Pulse Frequency: Increases with flame intensity, range 0-1000 pulses/sec.
Signal Processing: Pulses above 2.5 V are recognized as logic high; controllers count pulses within a 40 ms window.
4. ID Chip Identification
Connectors JR1, JS1, and JT1 are equipped with read-only ID chips storing the following information:
The I/O board reads this information during startup and compares it with expected values. If a mismatch is encountered, a hardware incompatibility fault is generated, preventing system problems caused by incorrect configuration.
V. Diagnostics and Configuration
1. Diagnostic Functions
The I/O board runs diagnostic tests for the IS200TRPGH1B, including:
| Diagnostic Item | Description |
| Relay Driver Feedback | Monitors relay driver control line to verify normal drive status |
| Relay Contact Feedback | Monitors actual relay status via normally closed contacts |
| Solenoid Power Bus | Monitors supply voltage for normal operation |
| Flame Detector Excitation Voltage | Monitors 335 V supply for overvoltage or undervoltage conditions |
| ID Chip Verification | Checks connector ID match, prevents hardware incompatibility |
If any diagnostic signal goes unhealthy (beyond limits), a composite diagnostic alarm is created. Diagnostic signals can be individually latched and reset with the RESET_DIA signal after returning to normal.
2. Configuration Method
The IS200TRPGH1B board has no jumpers or hardware settings. All configuration is done via controller software, including:
Relay output logic configuration
Flame detector parameter settings
Diagnostic threshold settings
This design simplifies on-site installation and maintenance, reducing problems caused by incorrect settings.
VI. Installation and Maintenance
1. Mounting Location
The IS200TRPGH1B board is typically mounted on a terminal board bracket inside the gas turbine control cabinet. In Mark VI systems, it connects to the VTUR board in the VME rack via cables with molded plugs. In Mark VIe systems, it connects to the TURHIC terminal board.
2. Installation Precautions
Ensure the board is firmly mounted and connectors are securely mated.
Cables should be correctly labeled to avoid misconnection.
Verify the board model is IS200TRPGH1B, confirming suitability for TMR applications.
Check that the ID chip information on the connectors matches the system configuration.
3. Maintenance Recommendations
Periodically inspect connectors for looseness.
Monitor relay status and flame detector signals via the diagnostic system.
If a relay failure is detected, replace the entire TRPG board promptly (relays on the board are not individually replaceable).
After board replacement, confirm that ID chip information is correctly recognized and no hardware incompatibility faults exist.
4. Replacement Procedure
Safety Warnings:
WARNING: To prevent electric shock, turn off relevant power and follow all GE safety procedures and lockout/tagout practices before replacing the board.
CAUTION: To prevent component damage caused by static electricity, treat the board with static sensitive handling techniques. Wear a grounding strap.
Replacement Steps:
Ensure the system is de-energized.
Open the control cabinet door and locate the IS200TRPGH1B board to be replaced.
Disconnect all cables (labeling them first is recommended).
Remove the screws securing the board and take out the old board.
Install the new board and tighten the screws.
Reconnect all cables as labeled.
Restore power and verify normal operation of the new board through the diagnostic system.
