Abstract: This paper discusses the development of a test bench system for a certain type of gas turbine starter. The system hardware is based on the PC-7483 board; the software is developed using CVI language under the WINDOWS environment; the main technical parameters of the turbine starter are monitored in real time, and the system automatically completes testing, data processing, and dynamically displays ground test data. Keywords: Gas turbine starter; Test bench; CVI; PC-7483; Development 0 Introduction The gas turbine starter test bench is a new type of fully automatic testing equipment test bench. During ground test, it can monitor the working status of the turbine starter in real time, save the data in real time, and display the processing results, turbine starter test parameters, and fault diagnosis results, effectively improving the automation level and testing accuracy of the testing equipment. 1 Overall Design Concept of Test Bench System The small turbine starter is driven by an electric motor. Through a computer-controlled fuel system, it delivers fuel to the engine according to the control program or operator instructions, controlling the engine's working status. The test system processes the signals transmitted by the sensors and displays the main working parameters and working status of the engine on the dial, and provides the required engine characteristic curves. The safety monitoring system senses changes in parameters and promptly provides fault information to ensure operational safety. The composition of the gas turbine starter is shown in Figure 1. The test bench mainly consists of a gas turbine starter, an eddy current dynamometer, a JZⅡ type torque and speed sensor, a test bench frame, fuel and lubricating oil tanks, a signal acquisition system, and a control system. The gas turbine starter is mounted on a test bench, which is equipped with interfaces for fuel, lubrication, control, and testing. The gas turbine starter connects to these systems via these interfaces. A computer-controlled fuel supply system controls the fuel supply according to a control program or operator instructions to regulate engine operating conditions, including controlling the starting fuel supply. The lubrication system provides the engine with clean, reusable lubricating oil at a suitable temperature. The control device controls the engine speed regulator to meet operational needs. The testing system transmits signals from sensors to a computer via a signal acquisition circuit. The computer processes the signals and displays the engine's main operating parameters and status. The safety monitoring system monitors changes in engine speed, exhaust temperature, vibration levels, and other parameters, issuing an alarm and automatically reducing operating conditions when safety limits are reached. The computer automatically performs speed control, data acquisition and conversion, characteristic plotting, indication, and data archiving. 2. System Hardware Design The system hardware is based on the PC-7483 board, a multi-functional integrated interface board designed for industrial PCs or PC-compatible machines. The board features 12-bit 16-channel A/D inputs, 4-channel 8-bit independent D/A outputs, 24-channel digital inputs/outputs, 3-channel pulse counter/timer interrupt, and other functions. Its working principle is shown in Figure 2. [align=center] Figure 2 PC-7483 Logic Block Diagram[/align] During operation, the corresponding circuits collect fuel pressure and temperature, lubricating oil pressure and temperature, vibration, and speed from the turbine starter and accessories. These signals are conditioned by sensors into 0-10V standard voltage signals, which are then read into an A/D converter and processed by the industrial control computer. The gas turbine and free turbine speed signals extracted from the engine are three-phase sinusoidal signals. Any two phases are conditioned into square wave counters. The experimental voltage amplitude is 0.2-10V, which is directly used as the gate signal of the counter. The speed is calculated using a periodic measurement method. The speed is read by the counter board and then calculated by the industrial control computer. The power supply and related accessory pump switch signals of the test bench are read into the high-speed digital I/O board after opto-isolation. The computer assists in judging the status of each pump and possible faults. The program background calculates technical parameters such as acceleration, rotor inertia, and starting time based on the speed and switch position. An alarm is issued when the starter experiences exhaust overheating or other faults to ensure safety. 3 System Software Design To achieve fuzzy monitoring of the gas turbine starter status, the system software uses the CVI language, which is known for its stability, strong control capabilities, and fast execution speed. The software provides a user-friendly graphical interface that is easy to understand and operate. During program execution, the test run is automatically monitored, the test run status is automatically analyzed, and test run data is processed and recorded. The program adopts a modular design, with the main loop including a system start-up module, a system operating status test and display module, a system operating status control module, and a test run curve parameter viewing module. The function and operation characteristics of each module are clearly defined. 3.1 Start-up Module As shown in Figure 3, this is the main operation display interface of the test bench. After opening the test bench system in the WINDOWS environment, the operator can operate it using the buttons on the control panel. Press the "Main Power" button to power on the equipment, and then press the "+27V", "+12V", and "+5V" keys in sequence to check. Then perform oil seal opening and cold start, and finally press the start button to perform the break-in test. In the main program interface, select the "Exit" button to exit the software running environment, and then turn off the power. [align=center]Figure 3 Main Operation Display Interface[/align] 3.2 Working Parameter Display Module As shown in Figure 4, in the working status display module, the program monitors parameters such as turbine starter speed, lubricating oil and kerosene pressure, exhaust temperature, and vibration value in real time, and displays them on the screen in dial form. In addition, it can also indicate the fluctuation of parameters such as speed and oil pressure, which is convenient for detecting fault symptoms such as suspension and surge. Moreover, it can indicate the dwell time of the test driver in some sensitive states to judge whether the test operation is standardized. [align=center]Figure 4 Test Stand Working Parameter Display Interface[/align] 3.3 System Working Status Control Module The system working status control interface is shown in Figure 5. The computer also analyzes and processes the measured parameters, intelligently analyzes the working status of the turbine starter, and judges whether the parameters such as speed, oil pressure, and exhaust temperature of the starter in the corresponding state meet the requirements; the operator operates the control interface according to the warning signals of the system working interface. When the system pressure exceeds the normal range, the system warning light flashes, and the operator takes measures according to the corresponding oil pump button. [align=center]Figure 5 System Working Status Control Interface[/align] 3.4 Test Run Curve Parameter Viewing Module After the test run is completed, the operator needs to analyze the obtained test run data. The test run parameter viewing module can reproduce the turbine starter test run process and display various parameters of the turbine starter, allowing the operator to intuitively analyze the turbine starter status based on the test run parameters. The test run curve parameter viewing interface is shown in Figure 6. [align=center]Figure 6 Test Curve Parameter Viewing Interface[/align] 3.5 CVI Programming Example Only the turbine starter main pump control statement is listed: int CVICALLBACK fuelpump (int panel, int control, int event, void *callbackData, int eventData1, int eventData2) { int P_Std,Std; switch (event) { case EVENT_COMMIT: GetCtrlVal (panelHandle, Testengine_POWER_SW, &P_Std); if (!P_Std) { MessagePopup ("Prompt message", "Please turn on the main power."); // SetCtrlVal (panelHandle, Testengine_FUELPUMP, OFF); break; } GetCtrlVal (panelHandle, Testengine_FUELPUMP, &Std); if (Std) relay_on(FULL_PUMP); else relay_off(FULL_PUMP); break; } return 0; } 4 Conclusion Innovation: This paper designs a brand-new gas turbine starter test bench system, using CVI language programming under the Windows environment, and successfully achieves data acquisition, transmission, and control with the PC-7483 integrated board. During development, several difficult problems such as real-time performance, anti-interference, and accurate measurement at low speeds were solved. It features high integration, high automation, high testing accuracy, and good reliability. The turbine starter test bench is an intelligent and integrated parameter acquisition and testing device that realizes comprehensive testing of the performance of gas turbine starters. References: [1] Fan Shangchun. Signal and Test Technology [M]. Beijing: Beijing University of Aeronautics and Astronautics Press, 2002. [2] Wu Jianqiang. Fundamentals of Digital Integrated Circuit Applications [M]. Beijing: Aviation Industry Press, 1994. [3] Chen Huiwen. Aircraft Engine Control [M]. Henan: Air Force First Aviation Academy, 2002. [4] Hu Jiwen, Chen Jianhui, Liu Jinning. Application of VC++ and DLL based on Lab Windows/CVI in Measurement and Control Technology [J]. Microcomputer Information, 2003.12:15-16.