The DS200TCQA Analog Input/Output Board (hereinafter referred to as the TCQA board) is a core signal processing module in the GE Speedtronic Mark V gas turbine control system, specifically designed for scaling and conditioning various analog signals. Installed in the control system's I/O cores <R1>, <R2>, and <R3>, this board serves as a critical hub for analog signal processing, handling multiple types of input and output signals including LVDT position signals, servo valve outputs, thermocouple temperature signals, 4-20 mA analog signals, vibration signals, relay drive outputs, pulse signals, voltage inputs, as well as generator and line signals. Through precision signal conditioning circuits and advanced algorithm processing, the TCQA board ensures these critical signals can be accurately and reliably read and utilized by the control system, providing important guarantees for the safe and stable operation of gas turbines.
Main Functions
1. Multi-Signal Type Processing Capability
The TCQA board possesses strong capabilities for processing various analog signals, including but not limited to:
LVDT/LVDR position sensor input signals
Servo valve drive output signals
Thermocouple temperature measurement signals
4-20 mA standard industrial signal inputs and outputs
Vibration sensor signals
Relay drive output signals
Pulse counting signals
Voltage input signals
Generator and line monitoring signals
2. Signal Conditioning and Scaling
The core function of this board is precise scaling and conditioning of raw analog signals, including:
Signal amplification or attenuation to appropriate voltage ranges
Noise filtering and interference suppression
Linearization and compensation processing
Signal isolation and protection
3. Data Communication and Exchange
The TCQA board exchanges data with other system components through various interfaces:
Data bus communication with the STCA board via the 3PL connector
Exchange of generator and line signals with the TCQC board via the JE connector
Acquisition of raw signals through various dedicated interfaces with terminal boards
4. System Integration Functions
As an important component of the Mark V control system, the TCQA board provides:
Compatibility with three control cores (<R1>, <R2>, <R3>)
Interface adaptation supporting different types of terminal boards
Configurable hardware jumper settings
Software-programmable signal processing parameters
Detailed Working Principles
1. Signal Processing Flow
The working principle of the TCQA board is based on precision analog signal processing technology. When raw signals generated by sensors are transmitted to the TCQA board through various terminal boards, they first enter the signal conditioning stage. At this stage, signals undergo impedance matching, filtering, and amplification processing to eliminate noise interference and adjust to appropriate level ranges. The processed signals then enter the analog-to-digital conversion stage, where analog signals are converted to digital signals for digital system processing. Finally, the processed digital signals are transmitted to other components of the control system through the data bus.
2. 4-20 mA Input Signal Processing
For 4-20 mA input signals, the TCQA board uses precision resistors as burden resistors to convert current signals into voltage signals for measurement. The transducer current produces a voltage drop across the burden resistor, which is read by the TCQA board and written to the I/O engine via the 3PL connector. Hardware jumpers on the TBQC terminal board are used to select the current range of the input signals, ensuring accurate measurement of signals across different ranges.
3. 4-20 mA Output Signal Generation
On the output side, the TCQA board generates 4-20 mA output signals through precision current source circuits, driving control devices connected to the TBQC terminal board via the JB connector. These output signals are typically used to drive various actuators and control devices, such as control valves and frequency converters.
4. Thermocouple Signal Processing
Thermocouple signal processing is one of the important functions of the TCQA board. Thermocouples are connected to the TBQA terminal board, with circuits on the TBQA terminal board providing thermocouple cold junction references, which are used by the TCQA board to calculate cold junction compensation. The board uses thermocouple inputs and compensation values to calculate the actual temperature read by the thermocouple, ultimately read by the I/O engine via the 3PL connector. Users can select thermocouple types and characteristic curves through I/O configuration constants, ensuring accurate measurement of different thermocouple models.
5. LVDT/R Position Signal Processing
Linear Variable Differential Transformers (LVDT) or Linear Variable Differential Reactors (LVDR) are used to detect actuator positions. Position signals are read from the TBQC terminal board via the JF connector, with scaled and conditioned signals used by the Control Sequence Program (CSP). Excitation signals for LVDT/Rs are written to the QTBA terminal board through the TCQC board. These sensors are typically used to regulate servo valve outputs, ensuring precise control of actuator positions.
6. Vibration Signal Processing
Vibration sensor signals are terminated at the TBQB terminal board in cores <R2> and <R3>, and read by the TCQA boards of cores <R1> and <R3> respectively. These signals are scaled and conditioned before being written to the control engine for use by the CSP for monitoring and protection functions. Users can select scaling values in the I/O configurator on the operator interface to adapt to different vibration measurement requirements.
7. Pulse Rate Signal Processing
The TCQA board contains circuits for scaling and conditioning pulse rate input signals, which are read from the TCQC board via the JE connector. These signals originate from TTL (Transistor-Transistor Logic) and magnetic pickup inputs, introduced through QTBA and/or PTBA terminal boards. Core <R1> receives high-pressure shaft speed inputs, while pulse rate input circuits on cores <R2> and <R3> can be used for other signal processing.
Hardware Configuration and Jumper Settings
The TCQA board provides flexible hardware configuration options, adaptable to different application needs through jumper settings:
J1 and J2 Jumpers: Used to select the operating mode of the mA output circuits, configured according to different output requirements.
J5 and J6 Jumpers: Used to configure the current range of mA outputs, selectable between 20 mA maximum or 200 mA maximum to adapt to different load requirements.
J7 Jumper: Used for the RS232 port, mainly for board testing and diagnostic functions.
J8 Jumper: Used to enable the oscillator, providing clock signals in specific application scenarios.
Users can view and configure these jumper settings through the hardware jumper screen on the operator interface, ensuring the board can meet specific application requirements. Detailed hardware jumper setting information is provided in Appendix A for technical reference.
Software Configuration and Parameter Settings
In addition to hardware configuration, the TCQA board supports rich software configuration options:
Thermocouple Configuration: Users can select thermocouple types and characteristic curves to ensure accurate temperature measurement.
Pulse Rate Settings: Configurable pulse signal ranges and processing parameters to adapt to pulse signals of different frequency ranges.
Vibration Signal Configuration: Setting vibration signal scaling factors and filtering parameters to optimize vibration monitoring performance.
LVDT Position Signals: Configuring position signal linearization parameters and range settings to ensure accurate position measurement.
4-20 mA Signal Processing: Setting input and output signal ranges, filter times, alarm thresholds, and other parameters.
These configuration parameters can be set and modified through the I/O configurator on the operator interface, providing users with great flexibility and convenience.
Application Fields and System Integration
The DS200TCQA Analog Input/Output Board is mainly used in the GE Speedtronic Mark V gas turbine control system, playing an important role in the following areas:
Power Plant Control Systems: Used for monitoring and control of gas turbines, ensuring stability and reliability of the power generation process.
Industrial Drive Systems: Providing precise signal processing functions in large industrial drive devices.
Process Control Systems: Playing a key role in industrial processes requiring precision analog signal processing.
Equipment Protection Systems: Providing protection for critical equipment through vibration monitoring and temperature monitoring functions.
The TCQA board is tightly integrated with other components of the Mark V control system, including STCA boards, TCQC boards, various terminal boards, and operator interfaces, together forming a complete and reliable control system solution.
