The DS200TCQCG1B Analog Input/Output Expander Board is a critical signal processing and interface expansion component within the General Electric (GE) Industrial Systems SPEEDTRONIC Mark V LM Gas Turbine Control System. Serving as a functional extension and signal hub for the TCQA analog I/O board, the TCQC board plays a vital role within the Mark V LM's analog control cores (<R1>, <R2>, <R3>). It is not only responsible for processing additional critical analog signals but, more importantly, provides the final output stage for the servo valve drive system, pre-processing of key pulse rate signals, and functions as the IONET network gateway connecting the Protective core (<P1>) and the Digital core (<Q11>).
This module is specifically designed to meet the extremely high demands of aeroderivative gas turbines for control precision, response speed, and system reliability. Its integrated multifunctional circuits and sophisticated hardware jumper configuration system enable the Mark V LM controller to flexibly adapt to the specific control requirements of various gas turbine models such as LM2500, LM6000, and LM1600. It is one of the core hardware platforms for implementing complex analog control and high-speed protection logic coordination.
2. Product Functions and Features
2.1. Core Functions
The DS200TCQCG1B module is typically installed in Slot 4 of the <R1>, <R2>, <R3> analog I/O cores, acting as an extension to the TCQA board and implementing the following core functions:
Servo Valve Drive Output Stage: The DS200TCQCG1B board is the final power stage and configuration center for four channels of bipolar servo valve current outputs (±10, ±20, ±40, ±80, ±120, ±240 mA). It receives control signals from the TCQA board and configures the output current range and feedback signal scaling at the hardware level through a precise on-board jumper network (J1-J16, J25-J36), allowing precise matching with different models and specifications of servo valves to drive critical actuators such as fuel valves and variable inlet guide vanes.
Servo System Protection Relay Control: Incorporates servo clamp relays and suicide relays. Under emergency conditions (e.g., emergency trip signal from TCEA), the servo clamp relay activates, applying a positive current to the servo valve to drive it to a home position. The suicide relay is controlled by the Control Sequence Program (CSP); when activated, it grounds the servo valve drive signal, allowing the valve to drift to a safe position under its bias.
Key Pulse Rate Signal Processing: Processes magnetic pulse signals from the PTBA protection terminal board (via TCQE) or the QTBA/TBQB terminal boards. In the <R1> core, it specifically processes the High Pressure (HP) shaft speed signal, passing it to the TCQA and STCA boards for control and primary overspeed protection. It also processes auxiliary pulse signals such as liquid fuel flow.
LVDT/LVDR Excitation Source: Provides 3.2 kHz, 7 V RMS excitation power for Linear Variable Differential Transformers/Reactors connected to the QTBA terminal board, used for precise measurement of valve or actuator position.
Analog Input Processing: Provides two 4-20 mA analog input channels. One is typically used for the compressor stall detection pressure transmitter (from TBQB), and the other for the megawatt transducer signal (from QTBA). These signals are sent to the STCA board for calculations.
Generator and Bus Feedback Signal Path: Serves as a conduit for synchronization check signals such as generator voltage and bus voltage. Signals from the TCTG board in the <P1> core pass through the TCQA to the TCQC, where they are conditioned before being sent to the STCA board for synchronization and paralleling functions.
IONET Network Gateway (TCQC in <R1> core only): This is one of the TCQC's most unique functions. It acts as the physical termination and master node of the I/O Network (IONET). Via the JX connector, it daisy-chains the three TCEA boards (X, Y, Z) in the <P1> protective core and the TCDA board in the <Q11> digital core. All fast and slow data from the protection system and digital I/O converge through this gateway and are transmitted via the 8PL connector to the STCA board in the <R1> core, ultimately merging into the control system database.
2.2. Design Features
High-Precision, Configurable Servo Drive: Offers extremely flexible servo output configuration through up to 32 hardware jumpers, allowing precise matching of servo valve impedance characteristics and feedback sensor scaling to ensure accurate and linear valve positioning.
Triple Safety Protection Mechanism: Combines software trip commands from the CSP, hardware emergency trip commands from the TCEA, and the on-board clamp/suicide relays to form a triple safety isolation at the software, hardware, and output levels. This ensures that fuel valves and other actuators can reliably enter a safe state in case of failure.
Signal Processing Hub: The DS200TCQCG1B is situated at the convergence point of TCQA, STCA, terminal boards (QTBA, TBQB), and the external network (IONET). It acts as a distribution center for analog signal flow, critical speed signals, and digital protection signal flow, effectively reducing system wiring complexity.
Critical Diagnostics and Monitoring: On-board circuitry can monitor power supply (+15V, -15V) status and limit the voltage supplied to proximity probe sensors via jumpers (BJ18, BJ20). Simultaneously, the status of the pulse and analog signals it processes can be monitored in real-time through the I/O Configurator and diagnostic tools.
Application Flexibility: The functional focus of the TCQC can be flexibly adjusted in different cores (R1, R2, R3). For example, in <R2> or <R3>, its pulse inputs and analog inputs may be used for other auxiliary monitoring functions, demonstrating the design's versatility.
3. Application Fields
The DS200TCQCG1B board is central to achieving advanced analog control and integrated protection in the Mark V LM control system, primarily used in the following fields:
High-Performance Power Generation: In large simple-cycle or combined-cycle gas turbine power plants, it precisely controls fuel metering valves and inlet guide vanes (IGV) to achieve fast load response, high-efficiency operation, and low-emission (especially DLE - Dry Low Emissions) combustion.
Mechanical Drive: Used in gas turbine controls for driving centrifugal compressors and pumps in natural gas or oil pipelines. Its high-precision servo control capability ensures compressor anti-surge control and precise flow regulation.
Marine Propulsion: Used in gas turbine propulsion systems for naval or commercial vessels. Its precise processing of HP shaft speed and multi-channel servo control are key to achieving rapid ship maneuverability and precise speed control.
Oil & Gas Production Platforms: Provides control for gas turbines used for power generation or mechanical drive on offshore platforms. Its rugged design suits the marine environment, and its integrated protection functions ensure platform safety.
In these applications, the DS200TCQCG1B board is not merely a simple I/O expander; it is the hardware cornerstone for implementing fast, precise closed-loop position control (via servo drive), integration of key safety protection signals (via the IONET gateway), and monitoring of core operating parameters (such as speed, power).
4. Product Advantages
Integration and Hub Status: A single board integrates three major functions: servo drive, key signal pre-processing, and network gateway. This greatly simplifies system architecture, reduces inter-board signal cabling, improves signal transmission reliability, and establishes a clear signal flow center.
Unparalleled Servo Control Flexibility: Provides an industry-leading, finely configurable servo drive solution via hardware jumpers. Users can precisely match the current output capability and feedback characteristics to the specific servo valve model on-site, achieving optimal control performance and valve lifespan.
Enhanced System Safety: The built-in servo clamp and suicide relays provide a final safety barrier independent of the processor. Combined with the hardware trip signal from TCEA via IONET, it forms a complete hardware protection chain from sensor to final actuator, aligning with the design philosophy of high Safety Integrity Levels (SIL).
Reliable Key Signal Processing: Dedicated to processing the most critical pulse signals, such as HP shaft speed. Its circuit design and signal paths are optimized to ensure real-time and accurate speed measurement, providing the most reliable data source for overspeed protection and load control.
Optimized System Communication: As the IONET gateway, it efficiently and reliably manages the data flow from the protection system and digital I/O. This enables the Control Engine <R> to promptly obtain all critical protection and status information while preserving the independence and fast response capability of the protection system (<P1>).
Exceptional Reliability Design: Utilizes mature design expertise accumulated by GE in the turbine control field. All components undergo strict screening and testing to ensure long-term, stable operation in the high-temperature, high-vibration, and high-electromagnetic interference environment of a turbine control room.
5. Installation, Configuration, and Maintenance Guide
5.1. Installation
The DS200TCQCG1B module must be installed in the card carrier of Slot 4 in the <R1>, <R2>, <R3> cores.
Before installation, ensure core power is OFF and follow ESD protection protocols.
Correctly connect all cables per Appendix B hardware documents: 2PL (power), JE (to TCQA), JFF (servo outputs to QTBA), JGG (signals to/from QTBA), JH (from TBQB), JJ (from TCQE, <R1> only), 8PL/19PL (to STCA), and JX (IONET to TCEA) in the <R1> core.
Special Note: When connecting ribbon cables, always align the "trace" (colored edge) with pin 1 of the connector. Many connectors are not keyed and require careful verification.
5.2. Hardware Configuration (Critical Step)
This is the most critical and error-prone step in TCQC board setup and must strictly follow drawings and jumper tables.
Servo Output Configuration (J1-J16, J25-J36):
Even-numbered jumpers (J2, J4...J16): Used to select feedback signal scaling, determining how the position feedback signal is interpreted.
Odd-numbered jumpers (J1, J3...J15): Used to select source output resistance, determining drive capability and current range.
Jumpers J25-J36: Provide additional feedback scaling options for servos 1-4, allowing a maximum current range of ±240 mA.
Configuration must exactly match the technical specifications of the connected servo valve. Incorrect configuration may cause control malfunctions or damage the valve.
Other Key Jumpers:
BJ18 and BJ20: Used to limit the +15V and -15V supply to external proximity probe sensors, protecting the sensors.
BJ21: Stall timer enable, set according to application requirements.
JP38, JP39: Magnetic pick-up gain settings for specific applications (e.g., liquid fuel flow).
After configuration, it must be verified against the online settings on the HMI's "Hardware Jumper Screen" to ensure consistency.
5.3. Software and System Integration
The DS200TCQCG1B board itself has no independent software configuration. Its functionality depends on:
The I/O configuration of the associated TCQA board (for servo control signals).
The I/O configuration of the STCA board (for pulse rate, synchronization check, etc.).
The I/O configuration and firmware of the TCEA and TCDA boards connected via its JX port.
When a core containing the TCQC (e.g., <R1>) is rebooted, the I/O Engine loads configuration data from the Control Engine <R> via COREBUS and passes it to the TCQC and associated boards via 3PL/8PL/IONET.
5.4. Maintenance and Troubleshooting
6. Safety Precautions
High Voltage Hazard: Servo valve drive loops can output currents up to ±240 mA. Related terminal blocks carry hazardous voltages. Before performing any maintenance or measurement, ensure controller power is completely disconnected and follow Lockout/Tagout (LOTO) procedures.
Critical Safety Functions: The servo clamp and suicide relays on the TCQC board are part of the safety shutdown system. Modifying or disabling any related circuits or jumpers (e.g., J1 jumper on the TCTG board) is strictly prohibited without fully understanding their function and safety implications.
Precise Configuration Requirement: Incorrect configuration of servo output jumpers may directly cause malfunction of controlled equipment (e.g., fuel valves), leading to serious incidents. Configuration work must be performed by trained, qualified personnel following valid engineering drawings and verified by a second person.
Electrostatic Sensitive Device (ESD): The DS200TCQCG1B board contains ESD-sensitive components like CMOS. Handling must be done with a grounded wrist strap on an anti-static workbench.
System Dependency: The DS200TCQCG1B's proper function is highly dependent on the TCQA, STCA, and other boards on the IONET network. Troubleshooting requires a systematic approach, tracing signals according to the flow diagrams.
