A Memory-Mapped File Approach for Transmitting Real-Time Turbine Engine Test Data to Data Validation Software Applications*

摘要

This paper describes a technique to transfer real-time aeropropulsion test data acquired in the Engine Test Facility (ETF) at the Arnold Engineering Development Center (AEDC) to data validation software applications. These applications utilize real-time test data to validate the measurements being acquired and to detect and diagnose faults as they occur. A Multi-Client Data Distribution Server Client Process (MULDDSCP) receives a list of desired test parameters from each of the active data validation applications and obtains the requested test data from the ETF data acquisition system. This real-time data is organized into data packets containing values for all requested parameters for a specific period of time. The MULDDSCP process writes these data packets to a memory-mapped file. A real-time server (RTSERV) process for each of the data validation applications retrieves the data from the memorymapped file. Communication with the memory-mapped file is synchronized among the MULDDSCP and all instantiations of the RTSERV through the use of a software semaphore controlled by the locking of bytes in an external file. A set of memory-mapped interface routines has been developed to provide transparent access to the memory-mapped file for local applications and for applications running remotely over a network. These routines are stored in a static library for UNIX?applications and in a dynamic-link library for Microsoft?Windows?applications.