Volume 34, Issue 3 (May 2006)
Story of MEGADAC 200: Keeping 200-Channel Legacy Data Acquisition Hardware Running by Developing a New Software Interface
This paper deals with a 16-bit 200-channel legacy data acquisition system from the 1980s—MEGADAC 200. MEGADAC is controlled by ASCII strings originating from the host computer connected via a serial (RS-232) port. The original software package for MEGADAC was written in BASIC and runs only in the DOS operating system on an Intel 386 processor, because of memory addressing issues. To interface MEGADAC from a modern computer, a new software interface [Object Oriented Blue Box (OOBLUEBOX)] was created using the C++ programming language. This paper describes details of object oriented implementation, architecture of the graphical user interface, and other implementation details including communication with the port. OOBLUEBOX enables one to define and calibrate internally energized strain gage sensors and externally energized sensors with voltage output, set up experiment tables for multichannel data acquisition, and perform data acquisition. Several special features, such as channel calibration and run-time plotting were also introduced.