IS200TREAH3A - Emergency Trip Terminal Board

IS200TREAH3A - Emergency Trip Terminal Board IS200TREAH3A - Emergency Trip Terminal Board

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Part No.: IS200TREAH3A
Manufacturer: General Electric
Series: Mark VI
Size: 33.0 cm high x 17.8 cm, wide
Technology: Surface mount
Temperature: -30 to 65oC
MPU pulse rate range 2 Hz to 20 kHz
MPU pulse rate accuracy 0.05% of reading
Voltage: 28 V dc max
Max. Current: 10 A dc
Leakage: 2.21 mA max
MPU input circuit sensitivity 27 mV pk (detects 2 rpm speed)
Availability: In Stock
Country of Manufacture: United States (USA)

Functional Description

IS200TREAH3A is a Turbine Emergency Trip Terminal Board developed by GE. It is a part of mark VI control system. The turbine emergency trip terminal board, is a vital component within the Mark VIe system, working seamlessly with PPRO turbine I/O packs to ensure the safety and efficient operation of the turbine. It facilitates various inputs and outputs, providing comprehensive functionality for emergency protection and control.


  • The terminal board features a well-organized layout with distinct wiring arrangements to ensure efficient connections for various components. At the top of the board, the voltage detection circuits and the breaker relay are wired to the I/O box terminals. These terminals provide a secure and accessible interface for connecting external devices related to voltage monitoring and breaker control.
  • On the lower terminals of the board, the passive pulse rate pick-ups are meticulously wired. These pulse rate pick-ups play a critical role in accurately sensing the turbine's rotational speed through toothed wheels. Their placement on the lower terminals allows for clear segregation and proper organization of the connections.
  • To facilitate easy and effective wiring, all the terminals on the TREA board are designed to plug into a header. This header provides a standardized and convenient connection point, ensuring reliable contact and reducing the risk of loose connections. Each terminal is capable of accepting up to a single 12 AWG wire, accommodating a range of wire sizes to suit different application requirements.
  • To tailor for specific speed input connections, users can utilize the provided configuration table. This table outlines the appropriate settings for jumpers P1 and P2. Jumper P1 allows users to select the desired fanning of the X section pulse rate pick-ups to the Y and Z PPROs. This configuration ensures that the turbine speed signals are accurately distributed and utilized by all three PPRO I/O packs, promoting precise monitoring and synchronization across the system.

Speed Inputs

  • When utilizing PPRO I/O packs that are directly mounted on the terminal board, there are two options available for configuring the speed inputs.
  • Option 1: Dedicated Speed Inputs
    • The first option involves providing each PPRO I/O pack with a dedicated set of three speed inputs from their respective terminal points. This configuration mirrors the setup used with the SPRO board. In this arrangement, each PPRO I/O pack receives its unique set of speed inputs, ensuring individual and independent monitoring of turbine speed.
  • Option 2: Fanned Speed Inputs
    • As an alternative, users have the option to configure the jumpers, P1 and P2, on the TREA board to fan the first three speed inputs (associated with the X pack) and distribute them to the Y and Z packs. When this configuration is selected, the terminal board points for Y and Z speed inputs become no-connects and should not be utilized. By fanning the speed inputs, the same set of speed signals is shared among all three I/O packs, promoting synchronization and uniformity in speed monitoring.
  • To ensure that the PPRO I/O packs are configured correctly for either fanned or direct speed inputs, a feedback signal is provided by the TREA. This feedback signal acts as a check to verify the jumper position on the TREA and the PPRO configuration align with each other. If there is a mismatch between the jumper position and the PPRO configuration, an alarm will be generated, alerting users to resolve the discrepancy and ensure proper alignment of the system.

Voltage Monitors

  • The placement of trip relays within the TREA exhibits a remarkable degree of flexibility. These trip relays can be strategically positioned at any point within a trip string, offering a level of adaptability that caters to the specific requirements of the system configuration. This dynamic approach to relay placement is inherent due to the inherent variability of the trip string circuit.
  • To facilitate this adaptability, the TREA incorporates three distinct, general-purpose, and isolated voltage sensor inputs. These inputs provide a versatile means to monitor various points within the trip system. The primary objective of these sensors is to capture and transmit voltage status data to the system controller, where corresponding actions can be initiated based on the received information.
  • The application possibilities for these isolated voltage sensor inputs are diverse and can be tailored to best suit the unique needs of the setup. As an example, these sensors can be utilized to monitor and sense critical aspects within the trip system, such as the power supply voltage for the two trip strings, denoted as "PWR." Additionally, they can be used to sense the voltage of the solenoid connected to the device being controlled by the trip relays, represented by SOL1 and SOL2.
  • While these specific applications are depicted in the board symbol's terminology, it's important to emphasize that the utility of these sensors is not limited to these examples alone. The sensors can be applied in a versatile manner, serving various roles based on the unique demands of the application. Their role is to provide a robust mechanism for capturing voltage data from different points within the trip system and conveying this crucial information to the system controller.


  • Jumpers JP1 and JP2: These are likely physical connectors or switches on the system's circuit board that can be moved to different positions to control the configuration.
  • Three X-section passive speed pickups: These are sensors or devices that are responsible for measuring speed in different sections of the system. They are passive, meaning they don't actively generate signals but rather detect existing signals.
  • S and T section PPROs: These are likely sections of the system or components called PPROs (possibly Processors or Processing Units) that receive and process the speed signals. The configuration determines which sections receive the signals.
  • Three R speed input: There are three speed inputs referred to as R, and the configuration is about directing these inputs to different sections.
  • The other two TMR sections: This indicates that there are two additional TMR sections that can receive the speed input from the R speed pickups.

Trip Relays

  • The trip relays in this system are constructed using sets of six individual form devices that are arranged in a voting pattern. When any two controllers within this setup decide to close, they create a conduction path through the set of relays.
  • Given the critical importance of detecting a shorted relay to maintain the reliability of the tripping function, each set of relays incorporates a sensing circuit. This sensing circuit comes into play when the command is issued to open the relays, and there is still voltage present across them. In this situation, the circuit performs the crucial task of identifying if one or more relays have become shorted. When such an anomaly is detected, a signal is generated, which is then transmitted to the PPRO I/O pack to trigger an alarm.
  • To ensure the utmost accuracy and reliability, the TREA sensing circuit takes into account relay commands from all three packs. This design approach prevents the occurrence of a false indication, especially in scenarios where one PPRO I/O pack decides to close the relay while the other two PTUR I/O packs opt to open. For visual clarity, the voting arrangement is visually represented using the TREA symbol.

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Frequently Asked Questions


What is IS200TREAH3A?
It is a Turbine Emergency Trip Terminal Board developed by GE

What is checked by the shorted contact detector in the PPRO I/O pack?
The shorted contact detector in the PPRO I/O pack performs regular checks on relay contacts to detect any instances of shorted relays. If a shorted relay is detected, the system triggers an alarm to alert users of this issue, ensuring prompt attention and maintenance.

What happens if there is a mismatch between the intention and actual position of the speed pickup fanning jumpers?
In the event of a mismatch between the intended and actual positions of the speed pickup fanning jumpers, the system generates an alarm. This alarm acts as a notification for users to resolve the discrepancy in the jumper settings, ensuring proper synchronization of speed inputs and maintaining accurate turbine speed monitoring.

How are diagnostic alarms handled when signals go unhealthy in the PPRO I/O pack?
When any of the monitored signals, such as shorted contact detection or speed pickup fanning, become unhealthy or deviate from their expected states, a composite diagnostic alarm called xxDIAG_PPRO is triggered. This alarm consolidates information on potential issues, making it easier for users to identify and address the root cause of the problem promptly.